Shadowknight12
2012-05-12, 11:26 AM
Hello. I was asked to compile a list of my houserules regarding undeath to be analysed or simply shared, and I thought that was a frankly awesome idea.
A warning or two, before we begin:
These rules are all modular. There is no need to take them all at once. You can pick and choose whichever you feel will improve your game, and ignore the rest.
These rules may not be suited for your playstyle. That doesn't mean your playstyle is wrong or that these rules are useless. They are merely tools created for a different need than yours.
CR is subjective. These rules make constant reference to CR, which is a notoriously unreliable measure. Never take the CR stated on a book as absolute truth. If you feel that your players would wipe the floor with the creature, lower its CR accordingly. If you feel your players would get sautéed by the creature on the first round, don't be afraid to raise it. It will take time for you to get used to it, but the best way to make use of these rules (and plan your encounters better) is to have a flexible and keen grasp on CR adjustment.
Now, onto the rules:
I. The Undead Mind
This was the first houserule I ever made, and the one I will sustain for as long as I keep gaming. It's a simple one.
The Undead type does not grant immunity to mind-affecting effects.
Clarification: This doesn't remove the immunity to mind-affecting effects that comes from having an Intelligence score of -, so mindless undead are still quite immune to mind-affecting effects.
Notes: This does not need to be a bad thing for the Undead type or the prospective necromancer. Remember that this means that now undead can be affected by morale bonuses and the like, which makes them ripe for being buffed by a properly optimised bard. And also keep in mind that if you absolutely need your undead BBEG to be immune to mind-affecting effects, there's always Mind Blank (http://www.d20srd.org/srd/spells/mindBlank.htm).
II. Undead Alignment
Second houserule I ever made, it's a bit of a thorny issue, as alignment is wont to be.
Undead creatures retain the alignment they possessed in life, unless otherwise stated by the DM.
Clarification: This makes all undead function, more or less, like the ghost (http://www.d20srd.org/srd/monsters/ghost.htm). This also allows leeway for the DM to create a vengeful, evil undead even if the person in life was kind and good, if that's what the plot dictates.
III. Spell Alignment
This one took a while to fully form, and is in fact a coherent compilation of several smaller houserules.
Warning: This houserule presupposes the principle that positive and negative energy are neither good nor evil. If you do not support this view or it does not apply in your campaign, please disregard this houserule.
The following spells lose the [Evil] descriptor: Animate Dead (http://www.d20srd.org/srd/spells/animateDead.htm), Contagion (http://www.d20srd.org/srd/spells/contagion.htm), Create Greater Undead (http://www.d20srd.org/srd/spells/createGreaterUndead.htm), Create Undead (http://www.d20srd.org/srd/spells/createUndead.htm), Curse Water (http://www.d20srd.org/srd/spells/curseWater.htm), Death Knell (http://www.d20srd.org/srd/spells/deathKnell.htm), Deathwatch (http://www.d20srd.org/srd/spells/deathwatch.htm), Desecrate (http://www.d20srd.org/srd/spells/desecrate.htm), Eyebite (http://www.d20srd.org/srd/spells/eyebite.htm), Nightmare (http://www.d20srd.org/srd/spells/nightmare.htm), Symbol of Pain (http://www.d20srd.org/srd/spells/symbolOfPain.htm), Unhallow (http://www.d20srd.org/srd/spells/unhallow.htm). Any mentions of "evil" or "unholy" in the spells' descriptions are to be replaced with something suitable for the campaign, or ignored as irrelevant fluff text. The following spells lose the [Good] descriptor: Bless Water (http://www.d20srd.org/srd/spells/blessWater.htm), Consecrate (http://www.d20srd.org/srd/spells/consecrate.htm) and Hallow (http://www.d20srd.org/srd/spells/hallow.htm). Any mentions of "good" or "holy" in the spells' descriptions are to be replaced with something suitable for the campaign, or ignored as irrelevant fluff text. It is highly recommended that the same principle is followed with spells from other sourcebooks.
Clarification: This leaves some spells with the [Good] and [Evil] descriptors, such as Holy Smite (http://www.d20srd.org/srd/spells/holySmite.htm) and Magic Circle Against Good (http://www.d20srd.org/srd/spells/magicCircleAgainstGood.htm). These are allowed to remain as they are because they pertain specifically to alignment. It is entirely up to the DM whether these spells retain the descriptors or not, according to the campaign she wishes to run.
Notes: Spells that do not pertain to undeath (such as Nightmare and Eyebite) were also included because of a more general design goal to streamline alignment and restrict unnecessary labelling. It is in the author's opinion that alignment descriptors should be reserved for spells that actually deal with alignment in a tangible, specific way, and not for things that the creators subjectively judged as "evil". The author also frowns upon the old designer ways of slapping the [Evil] descriptor on spells not meant to be used by PCs (such as undead-raising spells), and has attempted to do his best to revert that tendency.
Optional Rule:
Pertaining to the Consecrate/Desecrate/Hallow/Unhallow spells:
In addition to losing the alignment descriptor, they also allow the caster to decide which Magic Circle to emulate.
Any effects that relate to altars, holiness or unholiness are not present in the arcane version of the spells.
Humanoids buried within the area of an Unhallow spell have a 1% chance of arising as intelligent, free-willed undead (specific type of undead at DM's discretion) of the same CR as they were in life. Creatures unwilling to return to (un)life get a Will save to resist the effect. The DC is calculated normally for a 5th level spell (15 + caster's ability modifier).
IV. The Parts of a Creature
Warning: This is not D&D canon, but it's also not a houserule in the strictest sense. This is merely a way to make sense of D&D rules regarding the soul and the afterlife in a coherent whole.
An intelligent, sentient living creature (Humanoids, Monstrous Humanoids, Fey, Magical Beasts, Giants, most Dragons, some Plants and some Aberrations) is made up of five parts. The Body, the Echo (or the Shadow), the Mind, the Soul and the Anima.
All creatures that possess a Strength score possess a Body.
All creatures that possess an Intelligence score possess a Mind.
All creatures that possess both a Wisdom and a Charisma score possess both an Echo (or Shadow) and an Anima.
A creature must possess simultaneously an Intelligence, a Wisdom and a Charisma score in order to possess a Soul, but a creature that possesses all three mental scores does not necessarily possess a Soul.
Undead creatures can possess all five parts of the self, but not all do.
The Body is what allows the creature to interact physically with the world. Without a Body, a creature has no sense of taste or touch.
The Echo (or Shadow) is the psychological imprint of everything the creature has experienced in its life. It is what spells such as Reveille and Speak With Dead tap into. It remains along the Body, but it is not specified what happens to it after the Body finishes decomposing or turns to dust. It may ascend to join the Mind or the Soul, or it may remain haunting areas of importance to the creature (or the area around the creature's Body).
The Mind is the seat of the creature's logical reasoning and its ability to learn. It is also the seat of emotions, memories, learned skills, knowledge and mental acuity. Usually the Mind remains attached to the Soul even after death (and speaking of the Mind is the same as speaking of the Soul), but there are occasions, albeit extremely rare, where they might be separated (and as such, a distinction becomes necessary).
The Soul is the creature's essence, a distillation of its personality and the sum of its life experiences. The Soul is what possesses the creature's moral compass, conscience, and is the way through which it becomes attached to other creatures and the world. Which creatures have Souls varies from campaign setting to campaign setting. A creature without a Soul is incapable of having an alignment other than True Neutral.
The Anima is the force that animates the Body and is responsible for the creature's ability to move out of its own volition (even while under another creature's control), cast spells, use class features/skills/feats/SLAs/Ex and Su abilities/etc (in short, the ability to take actions). The Anima uses energy as a fuel to perform actions. This energy can take many forms, but the most common are Positive and Negative. A creature without an Anima cannot take actions.
Examples:
Corpse: Body + Echo.
Zombie: Anima + Body + Echo.
Wraith: Anima + Mind + Soul.
Wight: Anima + Body + Echo + Mind + Soul.
Soul Trapped by a Soul Bind (http://www.d20srd.org/srd/spells/soulBind.htm) spell: Soul (+ Mind?).
Soul Trapped by a Trap the Soul (http://www.d20srd.org/srd/spells/trapTheSoul.htm) spell: Mind + Soul + Body + Echo.
Soul freshly arrived in the afterlife: Mind + Soul.
This handily explains why a creature can be killed, then Soul Bound, and then its corpse can be reanimated as a zombie (but never an intelligent undead). This also explains why Soul Bind foils resurrection, since the resurrecting spell would lack one of the five parts that make up a living, intelligent creature. It also explains why you can't make a Wraith and a Zombie out of the same corpse (or multiple undead from the same corpse), since the Anima can only sustain one of the two (but you can question the corpse of an incorporeal undead with Speak With Dead, however).
Optional Rule A:
If the DM so wills it, a sixth component might be added to the five above, the Spark. The Spark would be the seat of creativity, change, growth, improvement, motivation, drive, life and whatever else the DM sees fit to include here. When a living creature dies, the Spark is snuffed out. Turning the creature undead does not rekindle the Spark, hence why undead can be depicted as static and unchanging. Only a powerful spell such as Raise Dead or the like can rekindle a snuffed Spark.
This optional rule doesn't really interact with mechanics that much, it's more of a flavour option for DMs so inclined. At the DM's discretion, other creature types (such as Constructs, Outsiders, Elementals and the like) may also lack a Spark despite having a Mind and Soul.
Optional Rule B:
Outsiders and Elementals are sustained by Planar and Elemental energies, respectively, while Constructs are sustained by the magic that animates them. As such, Elementals, Constructs and Outsiders are immune to both negative and positive energy, and require specific spells to heal/revive them (like an equivalent of the Repair Damage line for Outsiders and Elementals, or an equivalent of the Revive Outsider spell for Elementals and Constructs).
V. Animation And Spawn
Warning: The following rules are extensive and have only been playtested twice. Extreme care is recommended and feedback is highly encouraged.
Undead creatures under anyone's control (whether a spellcaster, rebuking cleric or the undead creature that spawned them) lose the ability to create spawn. Only free-willed creatures can create spawn. If an undead creature is freed, thereby gaining the ability to create spawn, and then is placed under someone's command, they immediately lose their ability to create spawn. Any spawn they possessed before being controlled are immediately freed.
An undead creature who is created or animated by a spell or by another undead creature's ability to create spawn receives a pool of Stygian Points equal to their HD. The creature loses this pool when it becomes free, but regains it (at the same value) if it falls under someone's control again.
An undead creature's SP pool diminishes every day at the stroke of midnight by an amount equal to the creature's CR (creatures with fractional CR do not lose fractions of a SP. Instead, they do not lose SP until the SP fractions add up to 1. For example, an undead creature with a CR of 1/3 would lose 1 SP every 3 days, an undead creature with a CR of 1/2 would lose 1 SP every two days and so on). If the creature has spent at least 24 consecutive hours within the area of a Desecrate spell, the amount of SP lost is reduced by 2 (to a minimum of 0). If the creature has spent at least 24 consecutive hours within the area of an Unhallow spell, the amount of SP lost is reduced by 5 (to a minimum of 0).
An undead creature who possesses an attack that deals ability damage must pay 1 SP for every dice of damage the attack inflicts every time it attacks. If the creature deals ability drain, it must pay 2 SP per dice instead. If the creature deals energy drain, it must pay 5 SP per negative level it inflicts. The SP are spent regardless of whether the attack hits or not, and whether the damage/drain is inflicted or not. If the creature has the option to attack without dealing ability/energy drain/damage, it may do so to avoid paying Stygian Points.
An undead creature must spend a number of Stygian Points equal to its CR in order to use a Special Attack or a Special Quality that requires activation (such as a Vampire (http://www.d20srd.org/srd/monsters/vampire.htm)'s Alternate Form or Gaseous Form). Creatures with fractional CR pay 1 SP.
A mindless undead creature whose Stygian Points pool is reduced to 0 is immediately destroyed. An intelligent undead creature whose Stygian Points pool is reduced to 0 points is immediately freed. At that point, it may choose to relinquish its grip on the Material Plane and return to the afterlife. If it chooses to do so, it is, for all intents and purposes, immediately destroyed.
Rebuking an undead creature gives it 1 SP per use of the Rebuke Undead ability. Some spells may recharge a creature's SP pool. As a general rule, they provide the undead creature a number of SP equal to three times the spell's level. A spell spent to recharge a creature's SP pool does not have any of its normal effects; it is effectively sacrificed. A creature's SP pool may exceed its HD and has no limit.
Stealing an undead creature's control from another creature or spellcaster maintains the SP pool as it was. If the method to gain control of it would increase the creature's SP pool (such as control through Rebuke Undead), it increases by the appropriate amount.
Successfully turning an undead creature makes it lose 1 SP from its pool. An undead creature who would be destroyed by a turning check gains a Will save (DC equals the turning check). If it succeeds, it is merely turned. If it fails, its SP pool is reduced to 0 and must make a Fortitude save (DC equals turning check) or be immediately destroyed. If the creature has Turning Resistance, it adds the value of its Turning Resistance to both saves as an untyped bonus.
Notes: This adds another layer of book-keeping to the table. Yes, I won't deny that. However, adding another resource to keep track of helps balance an undead creature's abilities, letting players play minionmancers while assuaging a DM's fears. The loss of spawn ability when under control prevents wightocalypses and the like, which is one of the main problems with undead as written.
Optional Rule:
Spells that can be sacrificed to increase Stygian Points are those of the Necromancy school that are specifically related to Negative Energy (such as Animate Dead, but not Astral Projection or Soul Bind).
VI. Reworked Spells
The spells Create Undead and Create Greater Undead allow the caster to create any type of undead they desire, provided the CR of the prospective undead to be created is less than or equal to CL/2 and the caster has completed a quest for the DM for each specific type of undead creature they wish to create. The corpse that is the target of the spell must be compatible with the type of undead the caster wishes to create (for example, a caster cannot use a dragon's corpse to create a wight). This does not change any of the spells' other parameters, it merely enhances the types of undead creatures that can be created.
Example: Araman, a level 11 Wizard, casts Create Undead on the corpse of a slain human. His intent is to create a Wraith (http://www.d20srd.org/srd/monsters/wraith.htm). The wraith is CR 5, which is less than 5.5, so it is within his limits. The wraith creature is compatible with the corpse, so that is allowed as well. Now, if he had not completed any quest to obtain the knowledge or ability to create wraiths with Create Undead and Create Greater Undead, the spell would automatically fail, consuming the expensive material components. However, because Araman's player arranged such a quest with the DM and recently completed it, Araman has the knowledge or ability to create wraiths and is able to do so without a hitch.
Clarification: The nature of the quest is entirely under the DM's prerogative, and with good reason: a DM needs to work out with her player what kind of creatures they will be bringing to the table, and how such addition will change the dynamics of the encounters. Sharing the control of what gets animated between the player and the DM provides maximum flexibility for the player while still allowing the DM to have the final say of whether certain kind of undead is easy, difficult or impossible to animate by a necromancer. Once the character completes a quest to create a given type of undead, they can create that type of undead with Create Undead or Create Greater Undead from then on.
Notes: It is strongly encouraged to only use this houserule paired with the one above regarding Animation and Spawn, or to work out with the prospective necromancer a way to avoid potentially wrecking the campaign. This is not a houserule to be implemented when you cannot trust your players.
Optional Rule:
To make Create Greater Undead a tempting choice (it's frankly lackluster when Create Undead does exactly the same, using a lower level spell slot), consider making the following adjustments:
Casting Time: 10 rounds (1 minute).
Range: Long (400 feet + 40 feet/CL).
Special: Does not require to be cast at night.
VII. Playing Undead
Use Oslecamo's Monster Classes (http://www.minmaxboards.com/index.php?board=34.0) for players wanting to play undead, instead of any of the "official" systems.
Notes: If the undead creature to be played does not exist, it is possible to make a contribution to the list.
VIII. Feeding Requirements
Unsatisfied with Libris Mortis's rules, I decided to take a stab at them myself.
All undead creatures must feed in order to continue existing. An intelligent undead creature has passions that keep it from passing on into the afterlife. These passions may be any sort of strong emotion that generates an attachment to the Material Plane, such as hatred, love, fear, anger, vengeance or a desire to look after an area or a creature.
An undead creature is considered "fed" for a day when it has spent at least 8 hours of it actively pursuing its passions (for example, a ghost who remains tethered to the Material Plane by a desire to look after its family is considered fed for a day once it has engaged in 8 hours of protecting its family members and watching over them).
An undead creature with the ability to inflict energy drain or ability damage/drain can also be considered "fed" on a day when it has used that ability successfully on a living creature a number of times equal to its CR (for example, a wight is CR 3, which means it needs to use its energy drain ability successfully on a living creature at least 3 times to be considered fed for that day).
Every day an undead creature goes without feeding, it takes 1 point of Wisdom damage. This damage may be healed normally only after the creature has fed. Until it has fed, the Wisdom damage does not heal normally and resists attempts to heal it magically. If an undead creature ever reaches 0 Wisdom due to a lack of feeding, it does not fall unconscious, but it must make a Will save (DC 10 + its HD + its Charisma modifier) to avoid losing control and engaging in the most expedient feeding method it has available. If the Will save succeeds, the undead creature may choose to relinquish its passions and pass on to the afterlife. If the undead creature does not relinquish its passions, it must make another Will save every successive hour afterwards, adding +1 to the DC for every successful save. Failing or succeeding the saves carries the same consequences as previously mentioned.
If an undead creature reaches Wisdom 0 due to a lack of feeding, fails any of the saves mentioned above, and is impeded from feeding, it begins to lose 1 HP per HD it possesses every hour it goes without feeding. This loss can be halted (but not reversed) for as long as the creature remains within the area of an Unhallow or Desecrate spell. Remaining within the area of a Hallow or Consecrate spell doubles the HP loss per day.
A mindless undead creature is incapable of having passions, and therefore it is incapable of feeding. Every day a mindless undead creature spends while not under any sort of control, it loses 1 HP per HD it possesses. This loss can be halted (but not reversed) for as long as the creature remains within the area of an Unhallow or Desecrate spell. Remaining within the area of a Hallow or Consecrate spell doubles the HP loss per day.
Notes: The passions of the undead can be explained by the absence of a Spark, if you're using that optional rule.
All right, that's about it. I'll update this if I realise I've missed something.
A warning or two, before we begin:
These rules are all modular. There is no need to take them all at once. You can pick and choose whichever you feel will improve your game, and ignore the rest.
These rules may not be suited for your playstyle. That doesn't mean your playstyle is wrong or that these rules are useless. They are merely tools created for a different need than yours.
CR is subjective. These rules make constant reference to CR, which is a notoriously unreliable measure. Never take the CR stated on a book as absolute truth. If you feel that your players would wipe the floor with the creature, lower its CR accordingly. If you feel your players would get sautéed by the creature on the first round, don't be afraid to raise it. It will take time for you to get used to it, but the best way to make use of these rules (and plan your encounters better) is to have a flexible and keen grasp on CR adjustment.
Now, onto the rules:
I. The Undead Mind
This was the first houserule I ever made, and the one I will sustain for as long as I keep gaming. It's a simple one.
The Undead type does not grant immunity to mind-affecting effects.
Clarification: This doesn't remove the immunity to mind-affecting effects that comes from having an Intelligence score of -, so mindless undead are still quite immune to mind-affecting effects.
Notes: This does not need to be a bad thing for the Undead type or the prospective necromancer. Remember that this means that now undead can be affected by morale bonuses and the like, which makes them ripe for being buffed by a properly optimised bard. And also keep in mind that if you absolutely need your undead BBEG to be immune to mind-affecting effects, there's always Mind Blank (http://www.d20srd.org/srd/spells/mindBlank.htm).
II. Undead Alignment
Second houserule I ever made, it's a bit of a thorny issue, as alignment is wont to be.
Undead creatures retain the alignment they possessed in life, unless otherwise stated by the DM.
Clarification: This makes all undead function, more or less, like the ghost (http://www.d20srd.org/srd/monsters/ghost.htm). This also allows leeway for the DM to create a vengeful, evil undead even if the person in life was kind and good, if that's what the plot dictates.
III. Spell Alignment
This one took a while to fully form, and is in fact a coherent compilation of several smaller houserules.
Warning: This houserule presupposes the principle that positive and negative energy are neither good nor evil. If you do not support this view or it does not apply in your campaign, please disregard this houserule.
The following spells lose the [Evil] descriptor: Animate Dead (http://www.d20srd.org/srd/spells/animateDead.htm), Contagion (http://www.d20srd.org/srd/spells/contagion.htm), Create Greater Undead (http://www.d20srd.org/srd/spells/createGreaterUndead.htm), Create Undead (http://www.d20srd.org/srd/spells/createUndead.htm), Curse Water (http://www.d20srd.org/srd/spells/curseWater.htm), Death Knell (http://www.d20srd.org/srd/spells/deathKnell.htm), Deathwatch (http://www.d20srd.org/srd/spells/deathwatch.htm), Desecrate (http://www.d20srd.org/srd/spells/desecrate.htm), Eyebite (http://www.d20srd.org/srd/spells/eyebite.htm), Nightmare (http://www.d20srd.org/srd/spells/nightmare.htm), Symbol of Pain (http://www.d20srd.org/srd/spells/symbolOfPain.htm), Unhallow (http://www.d20srd.org/srd/spells/unhallow.htm). Any mentions of "evil" or "unholy" in the spells' descriptions are to be replaced with something suitable for the campaign, or ignored as irrelevant fluff text. The following spells lose the [Good] descriptor: Bless Water (http://www.d20srd.org/srd/spells/blessWater.htm), Consecrate (http://www.d20srd.org/srd/spells/consecrate.htm) and Hallow (http://www.d20srd.org/srd/spells/hallow.htm). Any mentions of "good" or "holy" in the spells' descriptions are to be replaced with something suitable for the campaign, or ignored as irrelevant fluff text. It is highly recommended that the same principle is followed with spells from other sourcebooks.
Clarification: This leaves some spells with the [Good] and [Evil] descriptors, such as Holy Smite (http://www.d20srd.org/srd/spells/holySmite.htm) and Magic Circle Against Good (http://www.d20srd.org/srd/spells/magicCircleAgainstGood.htm). These are allowed to remain as they are because they pertain specifically to alignment. It is entirely up to the DM whether these spells retain the descriptors or not, according to the campaign she wishes to run.
Notes: Spells that do not pertain to undeath (such as Nightmare and Eyebite) were also included because of a more general design goal to streamline alignment and restrict unnecessary labelling. It is in the author's opinion that alignment descriptors should be reserved for spells that actually deal with alignment in a tangible, specific way, and not for things that the creators subjectively judged as "evil". The author also frowns upon the old designer ways of slapping the [Evil] descriptor on spells not meant to be used by PCs (such as undead-raising spells), and has attempted to do his best to revert that tendency.
Optional Rule:
Pertaining to the Consecrate/Desecrate/Hallow/Unhallow spells:
In addition to losing the alignment descriptor, they also allow the caster to decide which Magic Circle to emulate.
Any effects that relate to altars, holiness or unholiness are not present in the arcane version of the spells.
Humanoids buried within the area of an Unhallow spell have a 1% chance of arising as intelligent, free-willed undead (specific type of undead at DM's discretion) of the same CR as they were in life. Creatures unwilling to return to (un)life get a Will save to resist the effect. The DC is calculated normally for a 5th level spell (15 + caster's ability modifier).
IV. The Parts of a Creature
Warning: This is not D&D canon, but it's also not a houserule in the strictest sense. This is merely a way to make sense of D&D rules regarding the soul and the afterlife in a coherent whole.
An intelligent, sentient living creature (Humanoids, Monstrous Humanoids, Fey, Magical Beasts, Giants, most Dragons, some Plants and some Aberrations) is made up of five parts. The Body, the Echo (or the Shadow), the Mind, the Soul and the Anima.
All creatures that possess a Strength score possess a Body.
All creatures that possess an Intelligence score possess a Mind.
All creatures that possess both a Wisdom and a Charisma score possess both an Echo (or Shadow) and an Anima.
A creature must possess simultaneously an Intelligence, a Wisdom and a Charisma score in order to possess a Soul, but a creature that possesses all three mental scores does not necessarily possess a Soul.
Undead creatures can possess all five parts of the self, but not all do.
The Body is what allows the creature to interact physically with the world. Without a Body, a creature has no sense of taste or touch.
The Echo (or Shadow) is the psychological imprint of everything the creature has experienced in its life. It is what spells such as Reveille and Speak With Dead tap into. It remains along the Body, but it is not specified what happens to it after the Body finishes decomposing or turns to dust. It may ascend to join the Mind or the Soul, or it may remain haunting areas of importance to the creature (or the area around the creature's Body).
The Mind is the seat of the creature's logical reasoning and its ability to learn. It is also the seat of emotions, memories, learned skills, knowledge and mental acuity. Usually the Mind remains attached to the Soul even after death (and speaking of the Mind is the same as speaking of the Soul), but there are occasions, albeit extremely rare, where they might be separated (and as such, a distinction becomes necessary).
The Soul is the creature's essence, a distillation of its personality and the sum of its life experiences. The Soul is what possesses the creature's moral compass, conscience, and is the way through which it becomes attached to other creatures and the world. Which creatures have Souls varies from campaign setting to campaign setting. A creature without a Soul is incapable of having an alignment other than True Neutral.
The Anima is the force that animates the Body and is responsible for the creature's ability to move out of its own volition (even while under another creature's control), cast spells, use class features/skills/feats/SLAs/Ex and Su abilities/etc (in short, the ability to take actions). The Anima uses energy as a fuel to perform actions. This energy can take many forms, but the most common are Positive and Negative. A creature without an Anima cannot take actions.
Examples:
Corpse: Body + Echo.
Zombie: Anima + Body + Echo.
Wraith: Anima + Mind + Soul.
Wight: Anima + Body + Echo + Mind + Soul.
Soul Trapped by a Soul Bind (http://www.d20srd.org/srd/spells/soulBind.htm) spell: Soul (+ Mind?).
Soul Trapped by a Trap the Soul (http://www.d20srd.org/srd/spells/trapTheSoul.htm) spell: Mind + Soul + Body + Echo.
Soul freshly arrived in the afterlife: Mind + Soul.
This handily explains why a creature can be killed, then Soul Bound, and then its corpse can be reanimated as a zombie (but never an intelligent undead). This also explains why Soul Bind foils resurrection, since the resurrecting spell would lack one of the five parts that make up a living, intelligent creature. It also explains why you can't make a Wraith and a Zombie out of the same corpse (or multiple undead from the same corpse), since the Anima can only sustain one of the two (but you can question the corpse of an incorporeal undead with Speak With Dead, however).
Optional Rule A:
If the DM so wills it, a sixth component might be added to the five above, the Spark. The Spark would be the seat of creativity, change, growth, improvement, motivation, drive, life and whatever else the DM sees fit to include here. When a living creature dies, the Spark is snuffed out. Turning the creature undead does not rekindle the Spark, hence why undead can be depicted as static and unchanging. Only a powerful spell such as Raise Dead or the like can rekindle a snuffed Spark.
This optional rule doesn't really interact with mechanics that much, it's more of a flavour option for DMs so inclined. At the DM's discretion, other creature types (such as Constructs, Outsiders, Elementals and the like) may also lack a Spark despite having a Mind and Soul.
Optional Rule B:
Outsiders and Elementals are sustained by Planar and Elemental energies, respectively, while Constructs are sustained by the magic that animates them. As such, Elementals, Constructs and Outsiders are immune to both negative and positive energy, and require specific spells to heal/revive them (like an equivalent of the Repair Damage line for Outsiders and Elementals, or an equivalent of the Revive Outsider spell for Elementals and Constructs).
V. Animation And Spawn
Warning: The following rules are extensive and have only been playtested twice. Extreme care is recommended and feedback is highly encouraged.
Undead creatures under anyone's control (whether a spellcaster, rebuking cleric or the undead creature that spawned them) lose the ability to create spawn. Only free-willed creatures can create spawn. If an undead creature is freed, thereby gaining the ability to create spawn, and then is placed under someone's command, they immediately lose their ability to create spawn. Any spawn they possessed before being controlled are immediately freed.
An undead creature who is created or animated by a spell or by another undead creature's ability to create spawn receives a pool of Stygian Points equal to their HD. The creature loses this pool when it becomes free, but regains it (at the same value) if it falls under someone's control again.
An undead creature's SP pool diminishes every day at the stroke of midnight by an amount equal to the creature's CR (creatures with fractional CR do not lose fractions of a SP. Instead, they do not lose SP until the SP fractions add up to 1. For example, an undead creature with a CR of 1/3 would lose 1 SP every 3 days, an undead creature with a CR of 1/2 would lose 1 SP every two days and so on). If the creature has spent at least 24 consecutive hours within the area of a Desecrate spell, the amount of SP lost is reduced by 2 (to a minimum of 0). If the creature has spent at least 24 consecutive hours within the area of an Unhallow spell, the amount of SP lost is reduced by 5 (to a minimum of 0).
An undead creature who possesses an attack that deals ability damage must pay 1 SP for every dice of damage the attack inflicts every time it attacks. If the creature deals ability drain, it must pay 2 SP per dice instead. If the creature deals energy drain, it must pay 5 SP per negative level it inflicts. The SP are spent regardless of whether the attack hits or not, and whether the damage/drain is inflicted or not. If the creature has the option to attack without dealing ability/energy drain/damage, it may do so to avoid paying Stygian Points.
An undead creature must spend a number of Stygian Points equal to its CR in order to use a Special Attack or a Special Quality that requires activation (such as a Vampire (http://www.d20srd.org/srd/monsters/vampire.htm)'s Alternate Form or Gaseous Form). Creatures with fractional CR pay 1 SP.
A mindless undead creature whose Stygian Points pool is reduced to 0 is immediately destroyed. An intelligent undead creature whose Stygian Points pool is reduced to 0 points is immediately freed. At that point, it may choose to relinquish its grip on the Material Plane and return to the afterlife. If it chooses to do so, it is, for all intents and purposes, immediately destroyed.
Rebuking an undead creature gives it 1 SP per use of the Rebuke Undead ability. Some spells may recharge a creature's SP pool. As a general rule, they provide the undead creature a number of SP equal to three times the spell's level. A spell spent to recharge a creature's SP pool does not have any of its normal effects; it is effectively sacrificed. A creature's SP pool may exceed its HD and has no limit.
Stealing an undead creature's control from another creature or spellcaster maintains the SP pool as it was. If the method to gain control of it would increase the creature's SP pool (such as control through Rebuke Undead), it increases by the appropriate amount.
Successfully turning an undead creature makes it lose 1 SP from its pool. An undead creature who would be destroyed by a turning check gains a Will save (DC equals the turning check). If it succeeds, it is merely turned. If it fails, its SP pool is reduced to 0 and must make a Fortitude save (DC equals turning check) or be immediately destroyed. If the creature has Turning Resistance, it adds the value of its Turning Resistance to both saves as an untyped bonus.
Notes: This adds another layer of book-keeping to the table. Yes, I won't deny that. However, adding another resource to keep track of helps balance an undead creature's abilities, letting players play minionmancers while assuaging a DM's fears. The loss of spawn ability when under control prevents wightocalypses and the like, which is one of the main problems with undead as written.
Optional Rule:
Spells that can be sacrificed to increase Stygian Points are those of the Necromancy school that are specifically related to Negative Energy (such as Animate Dead, but not Astral Projection or Soul Bind).
VI. Reworked Spells
The spells Create Undead and Create Greater Undead allow the caster to create any type of undead they desire, provided the CR of the prospective undead to be created is less than or equal to CL/2 and the caster has completed a quest for the DM for each specific type of undead creature they wish to create. The corpse that is the target of the spell must be compatible with the type of undead the caster wishes to create (for example, a caster cannot use a dragon's corpse to create a wight). This does not change any of the spells' other parameters, it merely enhances the types of undead creatures that can be created.
Example: Araman, a level 11 Wizard, casts Create Undead on the corpse of a slain human. His intent is to create a Wraith (http://www.d20srd.org/srd/monsters/wraith.htm). The wraith is CR 5, which is less than 5.5, so it is within his limits. The wraith creature is compatible with the corpse, so that is allowed as well. Now, if he had not completed any quest to obtain the knowledge or ability to create wraiths with Create Undead and Create Greater Undead, the spell would automatically fail, consuming the expensive material components. However, because Araman's player arranged such a quest with the DM and recently completed it, Araman has the knowledge or ability to create wraiths and is able to do so without a hitch.
Clarification: The nature of the quest is entirely under the DM's prerogative, and with good reason: a DM needs to work out with her player what kind of creatures they will be bringing to the table, and how such addition will change the dynamics of the encounters. Sharing the control of what gets animated between the player and the DM provides maximum flexibility for the player while still allowing the DM to have the final say of whether certain kind of undead is easy, difficult or impossible to animate by a necromancer. Once the character completes a quest to create a given type of undead, they can create that type of undead with Create Undead or Create Greater Undead from then on.
Notes: It is strongly encouraged to only use this houserule paired with the one above regarding Animation and Spawn, or to work out with the prospective necromancer a way to avoid potentially wrecking the campaign. This is not a houserule to be implemented when you cannot trust your players.
Optional Rule:
To make Create Greater Undead a tempting choice (it's frankly lackluster when Create Undead does exactly the same, using a lower level spell slot), consider making the following adjustments:
Casting Time: 10 rounds (1 minute).
Range: Long (400 feet + 40 feet/CL).
Special: Does not require to be cast at night.
VII. Playing Undead
Use Oslecamo's Monster Classes (http://www.minmaxboards.com/index.php?board=34.0) for players wanting to play undead, instead of any of the "official" systems.
Notes: If the undead creature to be played does not exist, it is possible to make a contribution to the list.
VIII. Feeding Requirements
Unsatisfied with Libris Mortis's rules, I decided to take a stab at them myself.
All undead creatures must feed in order to continue existing. An intelligent undead creature has passions that keep it from passing on into the afterlife. These passions may be any sort of strong emotion that generates an attachment to the Material Plane, such as hatred, love, fear, anger, vengeance or a desire to look after an area or a creature.
An undead creature is considered "fed" for a day when it has spent at least 8 hours of it actively pursuing its passions (for example, a ghost who remains tethered to the Material Plane by a desire to look after its family is considered fed for a day once it has engaged in 8 hours of protecting its family members and watching over them).
An undead creature with the ability to inflict energy drain or ability damage/drain can also be considered "fed" on a day when it has used that ability successfully on a living creature a number of times equal to its CR (for example, a wight is CR 3, which means it needs to use its energy drain ability successfully on a living creature at least 3 times to be considered fed for that day).
Every day an undead creature goes without feeding, it takes 1 point of Wisdom damage. This damage may be healed normally only after the creature has fed. Until it has fed, the Wisdom damage does not heal normally and resists attempts to heal it magically. If an undead creature ever reaches 0 Wisdom due to a lack of feeding, it does not fall unconscious, but it must make a Will save (DC 10 + its HD + its Charisma modifier) to avoid losing control and engaging in the most expedient feeding method it has available. If the Will save succeeds, the undead creature may choose to relinquish its passions and pass on to the afterlife. If the undead creature does not relinquish its passions, it must make another Will save every successive hour afterwards, adding +1 to the DC for every successful save. Failing or succeeding the saves carries the same consequences as previously mentioned.
If an undead creature reaches Wisdom 0 due to a lack of feeding, fails any of the saves mentioned above, and is impeded from feeding, it begins to lose 1 HP per HD it possesses every hour it goes without feeding. This loss can be halted (but not reversed) for as long as the creature remains within the area of an Unhallow or Desecrate spell. Remaining within the area of a Hallow or Consecrate spell doubles the HP loss per day.
A mindless undead creature is incapable of having passions, and therefore it is incapable of feeding. Every day a mindless undead creature spends while not under any sort of control, it loses 1 HP per HD it possesses. This loss can be halted (but not reversed) for as long as the creature remains within the area of an Unhallow or Desecrate spell. Remaining within the area of a Hallow or Consecrate spell doubles the HP loss per day.
Notes: The passions of the undead can be explained by the absence of a Spark, if you're using that optional rule.
All right, that's about it. I'll update this if I realise I've missed something.