Creating a Necrocraft
In order to create a necrocraft, a spellcaster must use at least five undead creatures (or their corpses), all of which must be under the creator’s control, helpless, or slain. A larger undead or corpse can be used in place of two that are one size smaller. The creator must stitch, glue, or otherwise bind the parts together in the desired configuration, then cast animate dead and make whole to complete the construction (the material component cost of animate dead is 50 gp per Hit Die of the final necrocraft). The creator can’t create a necrocraft with more Hit Dice than her caster level. As with animate dead, the necrocraft is under the creator’s control when created. Note that creating a necrocraft requires casting a spell with the evil descriptor.
On another note, the text says that a typical Medium necrocraft is 7' tall and weighs 250 lbs. Using the square-cube law, that means a Large necrocraft would be 14' tall and 1 ton, a Huge one 28' tall and 8 tons, a Gargantuan one 56' tall and 64 tons, and a Colossal one 112' tall and 512 tons.
It magically gains weight as it gains size. Its weight is literally more than the sum of its parts.
EDIT: A note on acquiring corpses for necrocrafting; SWARMS! Swarms are not a single creature for targetting purposes meaning making zombies etc from swarm corpses doesn't really work. You instead wind up with a single zombie of the subject minus the swarm subtype. I recommend allowing players to just count a swarm as an equivalent creature of its combat space, or large for a 10'x10' swarm. That said RAW a dead swarm is just a big pile of separate corpses. This is especially useful with undead swarms as undead corpses are what we need for necrocrafts.
With one medium corpse being equal to two small corpses and 1 small corpse being equal to two tiny corpses we can calculate how many eety bitty bodies have to hit the floor before we can sew them together into an undead monstrosity.
Flying swarms have more component creatures than nonflying swarms.
A swarm of tiny flying creatures adds up to 250 medium-equivalent corpses.
A swarm of diminutive flying creatures adds up to 625 medium-equivalent corpses.
A swarm of fine flying creatures adds up to 625 medium-equivalent corpses too due to math shenanigans.
A nonflying tiny swarm gives us 75 medium-equivalent corpses.
A nonflying diminutive swarm is 187.
A nonflying fine swarm gives us 625 medium equivalent corpses.
- icefur during our discussion of this idea via chatGotta love the stupid math. 256 Fine creatures per Colossal. Yes, 256 fleas are the same size as a great wyrm red dragon, for PF equivalency's sake.
Spoiler: Larger Necrocrafts
*houserule limit of max of +5 CP
each +1 CP is +20% more bodies
each +1 CP is +0.5 CR
Medium Necrocraft CR 3
NE Medium undead
Init +1; Senses darkvision 60 ft.; Perception +0
AC 15, touch 11, flat-footed 14 (+1 Dex, +4 natural)
hp 26 (4d8+8)
Fort +2, Ref +2, Will +4
DR none; Immune undead traits
Speed 30 ft.
Melee 2 claws +5 (1d4+2)
Space 5 ft., Reach 5 ft.
Str 15 (+2), Dex 13 (+1), Con — (--), Int — (--), Wis 10 (+0), Cha 13 (+1)
Base Atk +3; CMB +5; CMD 16
Skills Fly +1, Stealth +1
SQ Construction Points
Construction Points (varies)
corpses: base 5, max 10
CP: base 2, max 7
CR: base 3, max 5
Carry Capacity: Light Load: 66 lbs., Medium Load: 133 lbs., Heavy Load: 200 lbs., Drag Weight: 1,000 lbs.
Large Necrocraft CR 5
AC 16, touch 10, flat-footed 15 (-1 Dex, +9 natural, -1 size)
hp 46 (7d8+14)
Fort +3, Ref +2, Will +5
Melee 2 claws +10 (1d6+6)
Space 10 ft., Reach 10 ft.
Str 23 (+6), Dex 11 (+0), Con — (--), Int — (--), Wis 10 (+0), Cha 13 (+1)
Base Atk +5; CMB +12; CMD 22
Skills Fly -2, Stealth -4
SQ Construction Points:
corpses: base 10, max 20
CP: base 3, max 8
CR: base 5, max7
Carry Capacity Light Load: 400 lbs., Medium Load: 800 lbs., Heavy Load: 1,200 lbs., Drag Weight: 6,000 lbs.
Huge Necrocraft CR 7
AC 13, touch 7, flat-footed 14 (-1 Dex, +6 natural, -2 size)
hp 65 (10d8+20)
Fort +4, Ref +2, Will +7
Melee 2 claws +15 (1d8+10)
Space 15 ft., Reach 15 ft.
Str 31 (+10), Dex 9 (-1), Con — (--), Int — (--), Wis 10 (+0), Cha 13 (+1)
Base Atk +7; CMB +16; CMD 28
Skills Fly -5, Stealth -9
SQ Construction Points:
corpses: base 25, max 50
CP: base 4, max 9
CR: base 7, max 9
Carry Capacity Light Load: 2,448 lbs., Medium Load: 4,896 lbs., Heavy Load: 7,360 lbs., Drag Weight: 36,800 lbs.
Gargantuan Necrocraft CR 9
AC 15, touch 5, flat-footed 16 (-1 Dex, +10 natural, -4 size)
hp 91 (14d8+28)
Fort +5, Ref +3, Will +9
Melee 2 claws +20 (2d6+14)
Space 20 ft., Reach 20 ft.
Str 39 (+14), Dex 9 (-1), Con — (--), Int — (--), Wis 10 (+0), Cha 13 (+1)
Base Atk +10; CMB +28; CMD 37
Skills Fly -7, Stealth -13
SQ Construction Points
corpses: base 50, max 100
CP: base: 5, max 10
CR: base: 9, max 11
Carry Capacity Light Load: 14,912 lbs., Medium Load: 29,856 lbs., Heavy Load: 44,800 lbs., Drag Weight: 224,000 lbs.
Colossal Necrocraft CR 11
AC 16, touch 1, flat-footed 17 (-1 Dex, +15 natural, -8 size)
hp 117 (18d8+36)
Fort +7, Ref +5, Will +11
Melee 2 claws +23 (2d8+18)
Space 30 ft., Reach 30 ft.
Str 47 (+18), Dex 9 (-1), Con — (--), Int — (--), Wis 10 (+0), Cha 13 (+1)
Base Atk +13; CMB +39; CMD 48
Skills Fly -9, Stealth -17
SQ Construction Points:
corpses: base 100, max 200
CP: base 6, max 11
CR: base 11, max 13
Carry Capacity: Light load: 88,576 lbs. (44 tons) Medium load: 177,408 lbs. (88 tons) Heavy load: 266,240 lbs. (133 tons) Drag weight: 1,331,200 lbs. (665 tons, or roughly 6 blue whales)
*Table corrected to match text.
Size HD CP CR Number of Undead Required Medium 4d8 2 3 5 Large 7d8 3 5 10 Huge 10d8 4 7 20 Gargantuan 14d8 5 9 40 Colossal 18d8 6 11 80
Necrocrafts have a number of Construction Points (CP) used to purchase abilities and defenses. A Medium necrocraft has 2 CP; differently sized necrocrafts have CP totals as detailed on the size chart on page 201. If a necrocraft is built with more CP than its size category would allow, its CR increases by 1 (minimum of +1) for every 2 additional CP spent. Unless otherwise stated, each of these abilities can be purchased only once.
Additional Movement (Ex, 1 CP): The necrocraft gains a new mode of movement (burrow, climb, fly [clumsy], or swim) at a speed equal to its base speed.
All-Around Vision (Ex, 2 CP): The necrocraft has an additional head facing in the opposite direction from its main head, or has extra eyes grafted at various points around its body. The necrocraft gains all-around vision.
Blade Fists (Ex, 1 CP): Up to two of the necrocraft’s claw attacks are replaced with sharpened bones or metal blades. These attacks deal 1d4 points of bleed damage. This ability can be selected multiple times, applying it to more claw attacks.
Bone Armor (Ex, 1 CP): Fortified with extra bone (perhaps including bones fused to its outer surface like armor), the necrocraft increases its natural armor bonus by 2. This ability can be selected up to three times.
Cannibalize (Ex, 1 CP): If the necrocraft is left near the corpse of a Medium or larger creature with discernible anatomy, it eats the corpse or tears off parts to repair its own substance. An undead creature consumed in this fashion heals the necrocraft 5 hit points plus 5 hit points per size category above Medium; any other type of creature restores only 1/5 this amount. Feeding takes 1 hour; any interruption (such as combat) requires it to start again.
Constrict (Ex, 1 CP): The necrocraft’s claw attacks gain the constrict ability. It must have grab before this ability can be selected.
Disease (Su, 1 CP): One of the necrocraft’s natural attacks is grafted with ghoul mouthparts, exposing a creature it hits to ghoul fever. Ghoul Fever: Bite, claw, or slam—injury; save Fort DC 13; onset 1 day; frequency 1/day; effect 1d3 Con damage and 1d3 Dex damage; cure 2 consecutive saves. The save DC is Charisma-based. A humanoid who dies of ghoul fever rises as a ghoul at the next midnight. A humanoid who becomes a ghoul in this way retains none of the abilities it possessed in life. It is not under the control of any other ghouls, but it hungers for the flesh of the living and behaves like a normal ghoul in all respects. A humanoid of 4 Hit Dice or more rises as a ghast.
Extra Attack (Ex, 1 CP): The necrocraft gains an additional bite attack or claw attack. This ability can be selected multiple times.
Extra Legs (Ex, 1 CP): The necrocraft gains two more legs, increasing its base speed by 5 feet and increasing its CMD against overrun and trip attempts by 4. This ability can be selected multiple times.
Extra Strength (Ex, 1 CP): The necrocraft’s Strength increases by 2 but its Dexterity decreases by 2. This ability can be selected twice.
Faster (Ex, 1 CP): The necrocraft’s base, burrow, climb, fly, or swim speed increases by 10 ft.
Grab (Ex, 1 CP): The necrocraft gains the grab ability with its natural attacks.
Metal Armor (Ex, 2 CP): Metal plates are bolted to or fused with the necrocraft, serving as armor and granting it a +4 armor bonus to AC.
Mostly Skeletons (Ex, 1 CP): Most of the necrocraft’s parts come from undead skeletons. The necrocraft gains DR 5/bludgeoning and resist cold 5. This ability can’t be added to a necrocraft with the mostly zombies ability.
Mostly Zombies (Ex, 1 CP): Most of the necrocraft’s parts come from zombies. The necrocraft gains DR 5/slashing and 5 additional hit points. This ability can’t be added to a necrocraft with the mostly skeletons ability.
Paralysis (Su, 2 CP): Up to three of necrocraft’s natural attacks gain the paralysis ability (1d4+1 rounds, DC 13, elves are immune to this effect). This graft requires the body of at least 1 ghoul. For an additional Construction Point, the paralysis ability can affect elves.
Reach Attacks (Ex, 1 CP): Up to two of the necrocraft’s natural attacks increase their natural reach by 5 feet. This ability can be selected multiple times.
Rending Claws (Ex, 2 CP): The necrocraft gains the rend ability, activating when both claws hit and dealing additional damage equal to the damage dice for one claw plus 1-1/2 times the necrocraft’s Strength bonus.
Rotting Flesh (Ex, 2 CP): Two of the necrocraft’s bite or claw attacks are poisonous. Poison: bite or claw—injury; save Fort DC 15; frequency 1/round for 2 rounds; effect 1d3 Constitution damage; cure 1 save.
Stench (Ex, 2 CP): The necrocraft has the stench ability (10- foot radius, Fort DC 15 negates, sickened for 1d6+4 minutes). This graft requires the body of at least one ghoul.
Trample (Ex, 2 CP): The necrocraft gains the trample universal monster ability as a special attack.
Animated Objects also utilize CP and with GM permission one could easily incorporate the Animated Object CP abilities into their Necrocraft as well.
Animated objects have a number of Construction Points (CP) used to purchase abilities and defenses in addition to those presented above. A medium animated object has 2 CP; differently sized objects have CP totals as detailed on the size chart on this page. If an animated object spends more CP than its size category would allow, its CR increases by 1 (minimum of +1) for every 2 additional CP spent. (Abilities marked with a * are from sources other than the core rulebook)
Additional Attack (Ex, 1 CP): Gains an additional slam attack.
Additional Natural Attack (Ex, 1 CP): The object gains an additional natural attack. The object must have an appropriate appendage or part for the natural attack. Source: PF #43
Additional Movement (Ex, 1 CP): Gains a new mode of movement (burrow, climb, fly [clumsy], or swim) at a speed equal to its base speed.
Augmented Critical (Ex, 1 CP): Increase the threat range for the Animated Object’s melee attacks by 1 or the threat multiplier by 1. This cannot combine with itself or with the piercing attack or slashing attack object abilities. Source: Ultimate Magic.
Burn (Ex, 1 CP): : The object gains burn (1d6) with its slam attacks. This can be applied multiple times. Its effects stack. Source: PF #43
Constrict (Ex, 1 CP): Gains constrict with its slam attacks (the object must have grab before it can take this ability).
Exceptional Reach (Ex, 1 CP): The object gains +5 feet of reach with one melee attack. Increase reach on all attacks for an additional +1 CP. Source: Ultimate Magic.
Faster (Ex, 1 CP): One of the object's movement modes increases by +10 ft.
Grab (Ex, 1 CP): Gains grab special attack with slam attacks.
Improved Attack (Ex, 1 CP): All the Animated Object’s melee or ranged attacks do damage as though it were one size category larger. A crafter must purchase Improved Attack separately for melee and ranged attacks. Source: Ultimate Magic.
Metal (Ex, 2 CP): The object is made of common metal. Its hardness increases to 10, and it gains a +2 increase to its natural armor bonus. Mithral objects cost 4 CP, and gain hardness 15 plus a +4 increase to natural armor. Adamantine objects cost 6 CP, gain hardness 20, and receive a +6 increase to natural armor.
Piercing Attack (Ex, 1 CP): Replace one melee attack with an attack that does the same amount of piercing damage and has a ×3 multiplier. Replace all melee attacks for an additional +1 CP. Object abilities that specify slam attacks do not work on piercing attacks. Source: Ultimate Magic.
Pull (Ex, 1 CP): The object gains a pull (5 feet) special attack with slam attacks (the object must have grab before it can take this ability). Source: PF #43
Ranged Attack (Ex, 2 CP): Replace one slam attack with a ranged attack. It does the same amount of damage, and has a range of 20 feet. Replace all attacks for an additional +2 CP. Object abilities that specify slam attacks do not work on ranged attacks. Source: Ultimate Magic.
Resistance (Ex, 2 CP): The object gains resistance 5 to one type of damage (acid, cold, electricity, or fire) chosen at the time of the object’s creation. This effect can be applied multiple times. Its effects do not stack; each time it is applied, it applies to a different type of damage. Source: PF #43
Slashing Attack (Ex, 1 CP): Replace one slam attack with an attack that does slashing damage and has either a 19–20 threat range (for blade-like attacks) or a ×3 threat multiplier (for axe- or scythelike attacks). Replace all melee attacks for an additional +1 CP. Object abilities that specify slam attacks do not work on slashing attacks. Source: Ultimate Magic.
Stone (Ex, 1 CP): The object is made of stone or crystal. Its hardness increases to 8 and it gains a +1 increase to its natural armor bonus.
Trample (Ex, 2 CP): The object gains the trample special attack.
Trip (Ex, 2 CP): The object gains the trip special ability with one of its slam attacks. Source: Ultimate Magic.
Animated objects can gain more CP by applying flaws, which hamper the object but provide additional CP to spend on beneficial abilities. If the CP gained in this way is not spent on beneficial abilities, its CR decreases by 1 for every 2 CP conserved.
Source: Pathfinder 43: Haunting of Harrowstone. All abilities presented below are from this source.
Brittle (Ex, +1 CP): The object gains vulnerability to cold.
Cloth (Ex, +1 CP): The object is made of thick cloth. Its hardness decreases to 0.
Clunky (Ex, +1 CP): Treat the object as though it had the staggered special quality.
Flammable (Ex, +1 CP): The object gains vulnerability fire.
Haunted (Ex, +1 CP): The object is haunted by a malevolent spirit. It takes damage from positive energy as if it were an undead creature and can be detect by detect undead.
Slower (Ex, +1 CP): One of the object’s movement modes decreases by – 10 ft.
The third party content Spheres of Power system brings us a couple of its own Construction Point abilities and flaws to the party.
Using these you can build a necrocraft which wears another necrocraft as a meatsuit and has its arms replaced by other necrocrafts. Just don't think too hard about taking the Hollow ability too many times and using Swallow Whole on a colossal creature while wearing another creature and having a few other creatures replace your limbs...
Spoiler: Spheres CP Abilities
Armor (Ex; 2 CP): The animated object is a suit of armor. When worn by another creature, it ceases to act as a creature of its own. Instead, any damage the wearer takes is dealt to the animated object instead; if the animated object loses all of its hit points, then the armor bonus it grants is reduced to +0. While worn, it grants its armor bonus to AC, as well as the benefits of any special abilities, as normal. As long as the animated object is still animated, it may be donned as a full-round action and removed as a swift action.
Durable (Ex; 1 CP): The animated object is exceptionally durable. It gains 5 additional hit points for each size category it has beyond Tiny, to a maximum of 30 additional hit points for Colossal animated objects. This can be applied multiple times, and its effects stack.
Fluid (Ex; 1 CP): The animated object is unusually fluid; it may squeeze through tight spaces as if it were two sizes smaller than it actually is.
Garrote (Ex; 1 CP): The animated object strangles creatures it grapples - it gains the strangle special attack (the object must have grab before it can select this ability).
Graft (Su; 1 CP): The animated object can serve as a replacement limb for a creature two size categories larger than it. While attached to a creature, the animated object ceases to act as a creature of its own. Instead, the creature benefiting from the graft ignores any penalties due to missing that limb, and gains one of the animated object’s natural attacks. If the animated object possesses any special attacks modifying that natural attack, the beneficiary of the graft gains it as well, using their size in place of that of the animated object. An animated object with graft may be attached to a creature with a DC 20 Heal check.
Hollow (Ex; 1 CP): The animated object gains the swallow whole special attack with its slam attacks; creatures swallowed by the animated object do not automatically take damage (the animated object must have grab before it may select this ability). This can be applied multiple times, each time increasing the animated object’s size category for the purposes of what creatures and objects it can grab and swallow by one.
Magic Item (Su; 1 CP): The animated object is some description of magic item. It may activate itself as if it were holding or wearing itself. Magic weapons may apply their enchantments to one of their natural attacks (for example, an animated +1 dragon bane longsword would have a +1 dragon bane slam attack).
Material Properties (Ex; 1 CP): The animated object’s natural attacks are considered to be weapons made from the animated object’s special material. The animated object must have metal or special material before it may select this ability.
Special Materials (Ex; 1+ CP) The animated object’s hardness is equal to the hardness of the Special Material it is made from. In addition, the animated object gains a natural armor bonus equal to the CP cost of this ability.
This ability costs 2 CP for every +5 increase to hardness gained from this ability, rounded up. If the special material has a hardness less than 10, it costs 1 CP instead.
If the material the animated object is created from has a hardness less than 5, use the Fragile flaw instead.
Toxic (Ex; 1 CP): The animated object is coated with a contact or injury poison. It gains the poison special attack with its slam attacks. The crafter may spend an additional CP to have that poison apply to all of its natural attacks instead.
Animated objects can gain more CP by applying flaws, which hamper the animated object but provide additional CP to spend on beneficial abilities. If the CP gained in this way is not spent on beneficial abilities, its CR decreases by 1 for every 2 CP conserved.
Aberration (Ex; +2 CP): The animated object is made from squirmy flesh instead of inorganic substances; change its type to aberration, give it a Constitution score equal to its Strength score, replace construct traits (Ex) with amorphous (Ex) and darkvision 60 feet, and replace its hardness with an equal amount of damage reduction bypassed by magic. It is still mindless.
Fragile (Ex; +1 CP): The animated object gains vulnerability to bludgeoning damage.
Immobile (Ex; +2 CP): The animated object has a base land speed of 0 feet, and may not have abilities or flaws applied which alter its base land speed or grant it new movement speeds.
The alien machine race of Aballonians have a list of Construction Point-like abilities that are in line with animated object and necrocraft abilities as well.
Spoiler: Aballonian CP abilities
Aballonian machines are capable of improving and adapting their designs. Each Aballonian starts out with one of the abilities listed below. For every two additional abilities it possesses, its CR increases by +1. Aballonians may also add the customizable abilities of animated objects, increasing their CRs by +1 for every 2 Construction Points spent in this way. (They are already considered metal.) Aballonians may adapt of their own volition, but it takes 1 day to add each additional ability beyond the first, and they must also possess the rare materials necessary to make such improvements. An ability can only be gained once unless stated otherwise.
Plasma Cutter (Ex, 1 CP) Gain a plasma cutter that deals 1d6 points of fire damage on a melee touch attack.
Advanced Treads (Ex, 2 CP) Gain advanced treads that increase base speed to 60 feet.
Modify Chassis (Ex, 2 CP) Modify chassis to gain a burrow, climb, or swim speed of 60 feet. This ability may be taken multiple times. Its effects do not stack. Each time it is taken, it applies to a new movement type.
Radar Dish (Ex, 2 CP) Add a radar dish that grants blindsight 120 feet.
Additional Attack (Ex, 1 CP) Gain an additional claw or slam melee attack (1d6 damage).
Lengthen Arms (Ex, 1 CP) Lengthen arms to extend reach by 5 feet.
Rending Attack (Ex, 2 CP) Gain the rend special attack (2 claws, 1d8+6).
Armor Plating (Ex, 1 CP) Add armor plating to gain a +4 natural armor bonus to AC.
Harden Systems (Ex, 3 CP) Harden systems to gain resistance 10 against a single energy type (acid, cold, electricity, or fire). This ability may be taken multiple times. Its effects do not stack. Each time it is taken, it applies to a new energy type.
*CP values extrapolated from existing CP abilities
Custom Spell: Animate Necrocraft
Spoiler: Animate Necrocraft
Source homebrew, modified Animate Objects
School necromancy; Level bard 6, cleric/oracle 6, occultist 6, psychic 6, skald 6, warpriest 6, witch 6
Casting Time 1 standard action
Components V, S
Range medium (100 ft. + 10 ft./level)
Targets one Small undead corpse per caster level; see text
Duration 1 round/level
Saving Throw none; Spell Resistance no
You combine and imbue inanimate undead corpses with mobility and a semblance of life turning them into a temporary necrocraft. Each such animated necrocraft then immediately attacks whomever or whatever you initially designate.
An animated necrocraft can be of any corporeal once undead corpses. You may animate one necrocraft made of a Small or smaller corpse or a corresponding number of larger corpses as follows: A Medium corpse counts as two Small or smaller corpses, a Large corpse as four, a Huge corpse as eight, a Gargantuan corpse as 16, and a Colossal corpse as 32. You can change the designated target or targets as a move action, as if directing an active spell. Regardless of how many corpses you animate with this spell only one necrocraft results per casting.
Alternatively, Animate Necrocraft can incorporate objects into the resultant necrocraft's structure at a rate of one small object per each two undead corpses animated; smaller objects being equal to larger objects apply as usual. Utilizing this option allows for the incorporation of appropriate Animated Object CP abilities.
Unlike Animate objects, Animate Necrocraft cannot be made permanent with a permanency spell.
Corpses animated by this spell cannot be reanimated as other undead in the future; They can, however, be reused for future necrocraft excepting that what was once many smaller undead corpses are now one larger undead corpse.
Mythic Animate Necrocraft
Source homebrew, modified Mythic Animate Objects
Animated necrocraft you create with this spell get the maximum number of hit points per level, gain a +4 bonus to their Strength ability scores, and have 1–1/2 times the normal number of construction points.
GM Note: Both necrocraft and animated objects suffer from the same problem once their additional CP rises too high — CR bloat. According to the published system (+2 CP = +1 CR), a Medium necrocraft with 32 additional CP has a CR of 19 (3 base + 16 from CP), making them a pretty tasty XP balloon (only 26 HP, but worth 204,800 XP). A cap for additional CP equal to twice the creature's starting CR should mitigate this problem a bit. For example, a Medium necrocraft could have up to 6 additional CP worth of abilities, since its starting CR is 3. A Large one could have up to 10 additional CP (CR 5 x2), a Huge one up to 14 additional CP (CR 7 x2), a Gargantuan one up to 18 additional CP (CR 9 x2), and a Colossal one up to 22 additional CP (CR 11 x2). Basically, the CR increase from added CP cannot more than double the creature’s starting CR.
GM Note 2: Even with the above limit in place, a necrocraft could still spend all of its (augmented) CP on an ability that can taken any number of times (such as Extra Attack or Extra Legs), leading to some hilariously unintended results (does the game really need a 5th-level cleric with access to Medium necrocrafts that have 10 claw attacks?). To mitigate this problem, a good limit on the number of times you can take any of the normally no-limit CP abilities is the necrocraft's base number of CP for its size (2 for Medium, 3 for Large, 4 for Huge, 5 for Gargantuan, and 6 for Colossal).
*Thanks again iceifur
GM Note 3: Necrocraft extra CP abilities run off of the increase to CR and CR doesn't matter towards Necrocraft creation at all. So the necromancer pays zilch for extra CP abilities. So by RAW either you cannot make Necrocraft with more CP or you can make a Necrocraft with ALL of the CPs for no extra cost.
Looking for a self imposed limiter houserule we see that increasing the size of the necrocraft increases the CR but costs 100% more bodies. Extrapolating we can say +1 CR increases the number of bodies by 50% extrapolating further 1/2 a CR, aka 1 CP, would increase the number of required bodies by 25%. Thus +1 CP equals +25% more base undead required. Again, to reiterate this is a houserule, but one taken from existing information.
*Thanks again, again iceifur
GM Note Addendum: Setting the rubric to +20% more base undead required per +1 CP is easier (due to the base numbers of bodies being multiples of 5), despite being less true to the derived values. If you want to stick to the original calculation, feel free to deal with those 1.25 extra bodies required for +1 CP to a Medium necrocraft, but remember that partial corpses make the necropuppy cry.
Under this system, if you're using the absolute max CP by doubling the CR, then a Medium with 8 CP would require 11 total bodies (5 base + 6 [6 CP x 1]), a Large with 13 CP would require 30 total bodies (10 base + 20 [10 CP x 2]), a Huge with 18 CP would require 76 total bodies (20 base + 56 [14 CP x 4]), a Gargantuan with 23 CP would require 184 total bodies (40 base + 144 [18 CP x 8]), and a Colossal with 28 CP would require 432 total bodies (80 base + 352 [22 CP x 16]).
An alternate limit would be no more than 5 extra CP, which would exactly double the number of required bodies.
If you go with the "no more than 5 extra CP" limit, you could switch back to the necrocraft's original number of required bodies (Medium 5, Large 10, Huge 25, Gargantuan 50, Colossal 100) to make the math prettier.
*Thanks continue for iceifur
Ways to boost CL for Necrocrafting
Anointing Oil item (Doesn't work for animating the dead, but might work on Undead creatures being woven into a Necrocraft via Animate Dead, ask your GM.)
Bloatmage Initiate feat
Candle of Invocation item
Death Knell spell
Deathwine (Potion of Cure Serious Wounds) spell
Equipment Trick (Aura Mastery) feat
Gifted Adept (Animate Dead) trait
Orange Prism (Flawed & Normal) Ioun Stone item
Outlander (Missionary) trait
Salt. Simply using salt (5sp per dose) will improve your Necromancy by +1.
Spell Perfection (Animate Dead) feat
Spell Specialization (Animate Dead) feat
Strand of Prayer Beads & Strand of Prayer Beads, Greater (Bead of Karma) item
Varisian Tattoo (necromancy) feat
Paizo boards thread on the subject