New Prestige Classes:

The Abyssym
”I have seen what lurks in the darkness. I have every right to fear it”
-Grimpt Telgon, Priest of Pelor

Shadows react differently with each type of magic it is paired with. When paired with arcane magic, it struggles to rip away, the force of which cancels out an opponent’s magic. When applied to the inherent magic of a warlock however, the exact opposite reaction ensues. The two forms of magic meld together, forming a mesh of shadowy magic. While children of night ascend into shadow, the Abyssym ascends into darkness.
BECOMING AN ABYSSYM
Due to the prerequisites, it is perhaps best to assume that most are shadowcasters. Cultists have no more difficulty meeting the prerequisites, but shadowcasters will be able to get the most versatility due to their larger selection of mysteries.
Entry Requirements
Alignment: Any Nongood
Skills: Knowledge (arcana) 6 ranks, Knowledge (the planes) 6 ranks, Spellcraft 6 ranks
Shadowcasting: Able to cast 2nd-level mysteries
Special: Eldritch blast 2d6

THE ABYSSYM HIT DIE: D4
Code:
Level   Base     Fort   Ref    Will   Special                           Mysteries
        Attack   Save   Save   Save
        Bonus
1        +0       +2     +0     +2     Eldritch Blast +1d6,              +1 level of existing mystery-using class/+1 level of existing invocation-using class
                                       See in Darkness
2        +1       +3     +0     +3     Abyssym of Cold                   +1 level of existing mystery-using class/+1 level of existing invocation-using class
3        +1       +3     +1     +3     Bonus Metashadow Feat             +1 level of existing mystery-using class/+1 level of existing invocation-using class
4        +2       +4     +1     +4     Eldritch Blast +2d6               +1 level of existing mystery-using class/+1 level of existing invocation-using class
5        +2       +4     +1     +4     Abyssym of Fear,                  +1 level of existing mystery-using class/+1 level of existing invocation-using class
                                       Eldritch Splice
6        +3       +5     +2     +5     Bonus Invocation                  +1 level of existing mystery-using class/+1 level of existing invocation-using class
7        +3       +5     +2     +5     Eldritch Blast +3d6               +1 level of existing mystery-using class/+1 level of existing invocation-using class
8        +4       +6     +2     +6     Abyssym of Darkness               +1 level of existing mystery-using class/+1 level of existing invocation-using class
9        +4       +6     +3     +6     Bonus Metashadow Feat             +1 level of existing mystery-using class/+1 level of existing invocation-using class
10       +5       +7     +3     +7     Greater Eldritch Splice,          +1 level of existing mystery-using class/+1 level of existing invocation using class
                                       Eldritch Blast +4d6
Class Skills (4 + Int modifier per level): Bluff, Concentration, Craft, Diplomacy, Hide, Intimidate, Knowledge (arcana), Knowledge (the planes), Listen, Move Silently, Search, Spellcraft, Spot, Use Magic Device

CLASS FEATURES
As an abyssym, you blend together your shadow magic and invocations with great ease.
Mysteries: At each level, you gain new mysteries and an increase in caster level as if you had also gained a level in a mystery-using class to which you belonged before adding the prestige class level. You do not, however, gain any other benefits a character of that classes would have gained. If you had more than one mystery-using class before becoming an abyssym, you must decide to which class to add each level for the purpose of determining caster level and mysteries known.
Invocations: At each level, you gain new invocations known and an increase in caster level as if you had also gained a level in an invocation-using class to which you belonged before adding the prestige class level (this does not include eldritch blast). You do not, however, gain any other benefit a characterof that class would have gained. If you had more than one invocation-using class before becoming an eldritch disciple, you must decide to which class to add each level for the purpose of determining caster level and invocations known.
Eldritch Blast:At 1st level, and then again at 4th, 7th, and 10th levels, the damage from your eldritch blast is increased by +1d6
See in Darkness (Su): Borrowing from shadow magic and fiendish blood alike, you improve your sight, allowing you to see through darkness and magical darkness out to 60 feet.
Abyssym of Cold (Ex): Starting at 2nd level, you can start to modify your eldritch blasts and mysteries through the interaction of energies that they generate. As a free action, you may add the cold descriptor to the next eldritch blast or mystery that you cast. Any creatures that are targeted or who are caught in the area of this eldritch blast or mystery take 1 cold damage/caster level (if a mystery) or invoker level (if an eldritch blast)
Bonus Metashadow Feat: At 3rd level, and again at 9th level, you gain any metashadow feat that you qualify for as a bonus feat.
Abyssym of Fear (Ex): Starting at 5th level, you can draw more power into your mysteries and eldritch blasts. As a free action, you may add the fear subschool and the mind-affecting descriptor to the next eldritch blast or mystery that you cast. Any creatures that are targeted or who are caught in the area of this eldritch blast or mystery must make a will save or become shaken for 1d4 rounds. This ability may be used with abyssym of cold.
Eldritch Splice (Ex): Starting at 5th level, the roiling powers of your magics start to mix. You may apply any eldritch essence or blast shape invocation to any applicable mystery. In addition, you may apply any applicable metashadow feat to your eldritch blast or an invocation, by using up a daily use of that mystery.
Bonus Invocation: At 6th level, an abyssym learns a new invocation, which must be an eldritch essence or blast shape invocation of a grade that they have access to.
Abyssym of Darkness: At 9th level, an abyssym can power their mysteries and eldritch blasts even further. As a free action, you may add the darkness descriptor to the next eldritch blast or mystery that you cast. If the area or target of the invocation or mystery is occupied by a spell with the light descriptor of a lower or equal spell level, the light is dispelled. If the mystery or eldritch blast has a target, a 20 foot-radius emanation, originating from that target, is covered in shadowy illumination for 1d4 rounds. If the mystery or eldritch blast has an area, that area is covered in shadowy illumination for 1d4 rounds. This ability may be used with abyssym of cold and abyssym of fear.
Greater Eldritch Splice (Su): At 10th level, your shadow magic and invocations have nearly roiled together to become one. Once per hour, plus one additional time per day per point of charisma bonus (if any), as a standard action, you may cast both a mystery and an invocation simultaneously. If the mystery would be cast as a spell, it is cast as a spell-like ability. If the mystery would be cast as a supernatural or extraordinary ability, so is the invocation. If both the mystery and the invocation allow saving throws, each one uses the higher of the two save DCs. This ability may not be used in combination with the abyssym of cold, abyssym of fear, or abyssym of darkness abilities.

PLAYING AN ABYSSYM
The depths of your power have been realized. By combining the your tainted blood with shadow magic, you have managed to grasp true power. You have learned that power invariably complements power and search out for any and all new sources to complement that which you already hold. You need not forsake or forget about your compatriots, for they are a power all their own, able to compensate for your shortcomings. Neither, however, do you desire to oppress them, for doing so would make them liabilities. More than your other pursuits, you seek to ascend into darkness, as darkness is your birthright and strength.
The Nightshade covenant sees you in much the same manner as the Votaries of Vecna view children of night, as a paragon of their cause. The Votaries of Vecna, for this reason, is not particularly friendly towards abyssyms, although membership is not denied to them should they truly wish for it. The Tenebrous Cabal admires your control of shadow magic and its interactions with invocations.

COMBAT
At low levels, you are just like any other mystery user or invocation user. As such, is may be wiser to remain at the back of the battlefield, harassing your opponents with mysteries, or, should you run out, with eldritch blasts.
As you advance, your shadow magic and invocations warp and fuse, granting you far greater versatility than practitioners of either path possess. Although this greatly increases your power, it is still best, throughout your career, to remain away from the fray.

ADVANCEMENT
As a practitioner of both learned shadow magic and innate invocations, your methods are somewhat improvised, but not random. Some of the processes must be actively learned and practiced in some manner, but the mixing of the two energies happens all on its own, triggered by increasing the ties to both forms of magic simultaneously. Your ascension to shadow, unlike that of the children of night, is arcane, rather than physical.
Your mental abilities are key as you level up, especially charisma, which makes your abilities more virulent. Of course, you now have to choose both mysteries and invocations carefully. Most of your mysteries will either have an area, modifiable through blast shape invocations, or will deal damage, which allows eldritch essences to function upon them.

RESOURCES
Abyssyms usually take up a live and let live approach towards other abyssyms. They have nothing that they can learn from one another and they naturally vie for sources of power if left in the same vicinity. When an abyssym joins a shadow magic organization, they are more expected to lead than to receive aid, although they may find some if they ask. The most reliable source of aid that an abyssym can call upon are the fiends from which they gained their power. Fiends (devils, demons, and yugoloths alike) respect their desire to ascend to shadow and are generally more willing to help them to such an end.

ABYSSYMS IN THE WORLD
“Children of night, as you call them, have quite their journey midway. I, meanwhile, intend to finish it.”
-Nelson Greymane, Abyssym

Abyssyms communicate a new viewpoint on shadow, seeing it as a midway point towards darkness. These enigmatic arcane practitioners have by far extended the range of what their powers can do through the mixing of two taboo forms of magic. Some players would be overjoyed to mix these dark magics together.

DAILY LIFE
Despite the scarcity of abyssyms in the world, it is easy to describe their everyday life. They typically work by night (or by dusk, if they should need some inconspicuous light). The first part of their day is spent studying or practicing their art, occasionally followed by some experimentation with their abilities. Afterwards, they proceed in their pursuit of power. This pursuit can take multiple forms, ranging from studying an ancient shrine in a library to exploring a tomb for a powerful item.
When abyssyms acquire a position of status, they treat it as another source of power, using it to gain more if possible. As abyssyms need to remain more or less free in their pursuit of power and ascension, they tend to ignore high-maintenance positions, sometimes leading to large problems.

NOTABLES
Despite their scarcity, rumors and stories of one particular abyssym have reached across the planes. Mae Kiar, it is said, managed to bodily and spiritually ascend into darkness after capturing the soul of the balor her family’s soul belonged to. The exact method by which she captured the soul, as no such method exists either in shadow magic nor invocations, remains unknown to this day. Mae Kiar today still lives as a deity of darkness and shadow (see later post for details).

ORGANIZATION
The Tenebrous Cabal officially greets abyssyms with open arms. Unofficially, they are not trusted and the cabal often sends spies to try and gain insight into their power. None has ever found their way onto the parliament of shadow.
The Votaries of Vecna will allow abyssyms to join, but they keep an even shorter leash on them, allowing nothing less than complete and utter compliance from them.
The Nightshade Covenant, which is dedicated to darkness as much as shadow, is the only group that really welcomes someone to aspires to merge their powers with darkness.

NPC REACTIONS:
As a combination of two untrusted sources of magic, very few people think highly of abyssyms. Common folk are normally frightened to death of them, seeing them as darkness incarnate. Stronger opponents seek to drive away such a threat, if possible. Warlocks tend to view you indifferently but most shadow magic users are unfriendly, as the basis of an abyssym’s philosophy is that darkness, and not shadow, is the true eternal power.
Nearly everyone is an enemy of an abyssym, from the paladins that wish them dead, to the mystery users who think them wrong, to the shadow organizations that think them wrong, to the everyday farmer who fears them as he fears death. Most warlocks are used to such solitude, however.

ABYSSYM LORE
Characters with ranks in Knowledge (arcane) or Knowledge (the planes) can research abyssyms to learn more about them. When a character makes a skill check, read or paraphrase the following, including the information from lower DCs.
DC 10:Abyssyms are dark practitioners of both shadow magic and invocations
DC 15:Abyssyms are never good news, and they are almost always evil and self-centered.
DC 20: The mixing of shadow magic and invocations allows them to meld together, lending the abyssym great versatility.
A bardic knowledge check or a Gather Information check can reveal the same information as these Knowledge checks, but in each case the DC is 5 higher than the given value.

ABYSSYMS IN THE GAME
Abyssyms are rare, as they not only need the tainted bloodline of a warlock but the dedication to learn shadow magic and the devotion to shadow that fuels the mixing of the two. For this reason, it is logical to assume that the PCs have neither heard of nor fought one yet
The abyssym is appropriate for players who like both component forms of magic, as the abyssym makes each more versatile. To make the player’s investment worthwhile, try to vary your encounters, for if the player is forced to rely on the exact same tactics in each encounter, then the experience may quickly become dull.

ADAPTATION
Due to the unique nature of both component classes and the ways that they are allowed to interact, it is much harder to adapt this class. To make it more PC friendly, you could easily reverse engineer the abyssym so that it is actually working towards light from darkness. This way, good players will have an equal chance to partake in the benefits of this class.

SAMPLE ENCOUNTER:
Encounters with abyssyms should take advantage of their tremendous versatility. Regardless of their opponent, they should appear as if they were completely prepared. Use of both mysteries and invocations also helps to hammer home exactly what they are fighting against.
EL 8: Nelson Greymane has been an abyssym for under a year, but he is slowly getting the hang of it. The PCs might run into him when researching an ancient power, or they might be in direct conflict with him if they stand in his way. Alternately, the PCs may be contacted to help Nelson reach a new reservoir of strength.
Nelson Greymane CR 8
Male Human Shadowcaster 3/Warlock 3/Abyssym 2
TN Medium humanoid (human)
Init +1; Senses See in Darkness; Listen +0, Spot +0
Languages Common, Abyssal, Infernal
AC 18, touch 11, flat-footed 17
hp 36 (8 HD) DR 1/cold iron
Fort +7, Ref +3, Will +9
Speed 30 ft. (6 squares)
Melee +2 Club +5 (1d6+1)
Ranged Eldritch Blast +6 (3d6)
Base Atk +4 ; Grp +3
Atk Options Abyssym of Cold
Special Actions Detect Magic, Still Mystery, Extend Mystery, Enlarge Mystery
Combat Gear 2 orbs of shadow (apprentice 1st), 2 Gems of Night
Invocations (CL 5; 1d20+5 to overcome SR)
Least—Breath of Night, Spiderwalk, Summon Swarm
Mysteries Known (CL 5th)
Apprentice paths:
3rd—Invisible Pyre (spell, 1/day)
2nd—Frigid Smoke (spell, 1/day), Sight Eclipsed (spell, 1/day)
1st—Cursed Flame (spell, 1/day), Steel Shadows (spell, 1/day)
Fundamentals
0—Mystic Reflections (supernatural, 3/day), Caul of Shadow (supernatural, 3/day), Arrow of Dusk (supernatural, 3/day)
Abilities Str 8, Dex 12, Con 12, Int 14, Wis 10, Cha 16
Feats Still Mystery, Enlarge Mystery, Extend Mystery, Weapon Focus (Eldritch Blast).
Skills Concentration +9, Hide +12 Intimidate +7, Knowledge (arcana) +7, Knowledge (the planes) +7, Move Silently +12, Spellcraft +6
Possessions combat gear plus +2 club and 400gp