I've homebrewed stuff before but never a full out PrC so please help me out and tear it to shreds:
Disciple of Karsus
While most Karsite's believe that it is there due to wipe out arcane spell casting and establish Karsus as a god, the Disciples of Karsus have a very different view of the world. The Disciples believe that Karsus's attempt to become a god went wrong due to sabotage by the established gods who were afraid of Karsus. Moreover, they believe that the inability of Karsites to use arcane magic was deliberately imposed by the gods so that no descendant of Karsus could similarly threaten the dominion of the gods.
Disciples of Karsus thus strive to be able to use arcane magic despite their nature. With immense concentration, effort, and sheer intelligence, aided by residual magical power supplied by binding to Karsus, they become able to use arcane magic.
Spellcraft 1, Knowledge(arcana) 8, Concentration 3 rank
Favored Vestige: Karsus
Must be a Karsite
Must be able to bind 3rd level vestiges and must have bound Karsus, Hubris in the Blood, at least once.
Bluff, Concentration, Decipher Script, Gather Information, Intimidate, Knowledge(arcana), Knowledge(history), Knowledge(the planes), Knowledge(religion), Profession, Spellcraft, Sense Motive, Use Magic Device
Skill-points per level:
A Disciple of Karsus gains no additional armor or weapon proficiencies.
Disciple of Karsus
|Level||Base Attack Bonus ||Fort Save||Ref Save||Will Save||Special|
|Spellcasting, Permanent Binding, Soul Binding +1|
|Blood of Karsus, Wrath of Karsus 1/day, Soul Binding +2|
| Bonus feat, Detect Vestige, Soul Binding +3|
|Wrath of Karsus 2/day, Great Concentration, Soul Binding +4|
|Direct Spell Healing, Intertwined Souls, Soul Binding +5|
|Rapid Karsus's Touch, Soul Binding +6|
|Permanent Binding, Improved Karsus's Touch, Soul Binding +7|
|Wrath of Karsus 3/day, Improved Karsus's Senses, Soul Binding +8|
|Bonus Feat, Power of the Vestiges, Karsus's Quickened Touch, Soul Binding +9|
|Arcana Triumphant, Advanced Spell Learning, Soul Binding +10|
At each level, your soul binding ability improves as if you had gained a level of the Binder class. This increases your effective binder level, the bonus you receive on binding checks, and the level and number of vestiges you may bind. You do not, however, gain any other abilities or advantages a Binder would have gained.
The remaining magical power in Karsus allows the Disciple of Karsus some limited spell arcane spell casting even though Karsite's are normally unable to cast arcane spells. The Disciple of Karsus gain per a level daily spell slots as the table below. You cast prepared spells. The great difficulty of casting magic in this way means that the Disciple of Karsus can only cast a limited number of spells.
To cast a spell, a Disciple of Karsus must have an Intelligence score of at least 10 + the spell’s level, so a Disciple of Karsus with an Intelligence of 10 or lower cannot cast these spells. Disciple of Karsus bonus spells are based on Intelligence, and saving throws against these spells have a DC of 10 + spell level + the Disciple’s Intelligence bonus. When the Disciple gets 0 spells per day of a given spell level he gains only the bonus spells he would be entitled to based on his Intelligence score for that spell level.
At each level the Disciple gains new spells as follows: The Disciple starts with 2 cantrips known and 1st level spell known. At 2nd level the Disciple gains 1 additional cantrip known and another 1st level spell. At every level after that the Disciple gains 2 spells of level up to the highest level spell the Disciple is able to cast.
The Disciple of Karsus otherwise prepares spells just like a wizard.
Although the Disciple of Karsus has great difficulty mastering even a few spells, the intense work it takes a Disciple to learn a spell means that once learned a Disciple has that spell so thoroughly understood that they have no need to prepare it from a spellbook. For all purposes, a Disciple of Karsus is treated as having spell-mastery of all spells he knows from this class.
Spellcasting from Disciple of Karsus can be used to qualify for other prestige classes but it cannot be used to qualify for any prestige class that advances spell casting. For example, you can use it to go into Arcane Archer but not Arcane Trickster.
Disciple of Karsus Spellcasting
You are permanently bound to Karsus. You must still make a daily binding check to determine the nature of the pact.
Blood of Karsus (ex)
Your arcane study and your descent from Karsus give you a stronger connection with Karsus than that of other binders. The Binding DC to bind Karsus for you is reduced to 20. Furthermore, Karsus's Heavy Magic ability increases save DCs by 3 rather than by 2.
Wrath of Karsus (su)
Once a day when using Karsus's touch you may add to your dispel check a bonus equal to half your class level. You may use this twice a day at 4th level, and three times a day at 8th level
At 3rd level you gain one bonus feats. These feats may be any feats that could be a wizard bonus feat or any of the feats Defense Against the Supernatural, Empower Supernatural Ability, Enlarge Supernatural Ability, Expel Vestige, Extend Supernatural Ability, Favored Vestige, Favored Vestige Focus, Ignore Special Requirements, Rapid Pact Making, Rapid Recovery, Skilled Pact Making, Sudden Ability Focus or Widen Supernatural Ability. You must still meet all the other prerequisites for the feat. You gain another bonus feat at 9th level.
Detect Vestige (su)
Your familiarity with vestiges and Karsus's magic have allowed you to detect the presence of vestiges. you gain the ability to use Detect Vestige as a supernatural ability. You may use this once a day at 3rd level, twice a day at 6th level, 3 times a day at 9th level and at will at 10th level.
Your intense effort to study arcane magic despite your nature has made you learn how to concentrate particularly effectively. You gain skill focus(concentration) as a bonus feat. Also, whenever you would make a concentration check due trying to cast a spell while distracted you may sacrifice a spell slot equal to or of higher level than the spell you are casting to automatically succeed on the concentration check. This is an extraordinary ability.
Direct Spell Healing (su)
You have learned to channel your own arcane magic into your spell healing ability. You may as a standard action sacrifice a spell slot and heal damaged points equal to twice that spell's level just as if you had absorbed a spell of that level with your spell resistance.
Intertwined Souls (ex)
Your connection with Karsus is not so much a standard binding but rather a deep interweaving of your soul with Karsus. As a result, you are not counted as being bound to Karsus for purposes of determining the maximum number of vestiges to which you can bind.
Rapid Karsus's Touch (su)
When you use Karsus's Touch you may sacrifice a spell slot. If you do reduce the number of rounds you need to wait before reusing Karsus's Touch by the level of the spell slot. So for example, if one sacrificed a 2nd level spell slot one would only need to wait 3 rounds before being able to reuse Karus's Touch. If the slot sacrificed is 5th level or higher you may immediately reuse Karsus's Touch.
Improved Karsus's Touch (su)
Your arcane knowledge and deep connection to Karsus improves your use of Karsus's Touch. Three times daily you may use Karsus's Touch with a ranged touch attack with a range of 30 feet.
Improved Karsus's Senses (su)
Your use of Karsus's sense are improved. You are not dazzled by the presence of overwhelming auras. Also, you may when using Karsus's Senses gain information more quickly. When using Karsus's Senses to determine the associated schools of magic for auras, you may make this determination two auras a round rather than just one.
Power of the Vestiges (su)
You have learned from your ability to channel power from Karsus's vestige and can now apply it in a limited fashion to other vestiges. For every vestige you have bound to you other than Karsus your effective caster level for Disciple of Karsus increases by 1.
Karsus's Quickened Touch (su)
You may use Karsus's Touch as a swift rather than a standard action if you sacrifice a spell slot slot of 4th level or higher.
Advanced Spell Learning (su)
You're great arcane power and intelligence allow you to learn new additional spells if they are of low level. You may learn additional 0th or 1st level spells on the sorcerer/wizard list simply by studying spellbooks or scrolls that contain the spells. Doing so takes 8 hours of work per a spell, and the intense magical effort put in costs you 500 xp for cantrips and 1000 xp for first level spells.
Your years of perseverance and the power of Karsus have paid off. You have regained some of the great spellcasting ability of Karsus that is your rightful heritage. You may now take ranks in any arcane spell casting class. You add 10 to your effective caster level for any arcane casting class other than Disciple of Karsus. Moreover, if you take levels in any such class you are treated as knowing all spells for that class that you know as a Disciple of Karsus, as long as they are on the class list. If you gain any levels in a class that requires preparing spells from a spellbook you are automatically treated as having spell mastery of all spells that you gained as a Disciple of Karsus.
Playing a Disciple of Karsus
You have two goals: increasing your arcane power and bringing Karsus to godhood. To accomplish your goals you are not averse to using other vestiges as tools.
You understand that you must carefully conceal your true nature. The vast majority of Karsites consider Disciples of Karsus to be heretics for their attempts to gain arcane power. And since binding is feared and not well-treated by the larger magical community, you have nowhere to turn to but other Disciples of Karsus. When adventuring you likely disguise your true nature by pretending to be a wizard or other more standard spell-caster.
So what do people think? My most serious worry is that there are too many levels. By the time one gets to the capstone ability which allows one to take other spellcasting classes one is effectively at level 17 since one needs to be level 5 to meet the requirements and Karsite is a +2 adjustment. Should I shorten the total number of levels?
(Edit: I think this is ok now with the higher level spell casting).
Edit: I increased spellcasting to include 6th level spells. I removed special spells given at specific levels and added Improved Karsus's Touch and Rapid Karsus's Touch. I also made a few grammar and spelling corrections and clarified spellcasting rules.