Are there any classes that resemble an occultist of the Lovecraftian mythos, or have such a feeling, except the alienist and the flesh warper? The aberration blood feats are interesting but just give flavor; I am searching for something more solid, a base or prestige class.
The Lovecraftian feel is broader then most people think: You could easily have NPCs with the Dread Pirate PrC involved in your version of The Shadow Over Innsmouth. I also based this on what I could see appearing in Lovecraft's stories, rather then just Mythos type creatures (Thus degenerate humans and such are also fair game, as are charismatic cult leader types, etc). Howard, a good friend of Lovecraft's, also published stories in the same vein, but a bit more hack and slash. I've denoted classes that would work well with his books.
The other idea is to take rules from a class, then rewrite the theme and feeling of it to be more lovecraftian: Example: Bear Warrior instead is embracing his Shoggoth heritage, and becomes more and more unnatural as he goes up in levels.
However here are some which I could think would be useful or lend themselves to Lovecraftian work:
- Animal Lord (Sharklord, Apelord [Degenerate humans])
- Master of Many Forms (Change into Ooze and Abberations)
- Ghostfaced Killer (More Howardian horror, but it goes well with Lovecraftian horror)
- Acolyte of the Skin
- Blood Magus
- Effigy Master (With horrible enough effigies)
- Master Transmogrifist (Transformation is a running Lovecraftian theme)
- Black Flame Zelot (With some re-themeing, but evil assassins would tie in well with say, The Red Hook Horror)
- Evangilist (For evil priests)
- Geomancer (Drift mutates you in similar ways to The Innsmouth Look)
- Nightmare Spinner
- Wild Soul (If given a darker slant, change the creatures to look more horrific, while using the same stats)
- Bear Warrior (Except replace bear with deep one, shoggoth, something)
- Eye Of Grumpsh (Cultist, replace Grumpsh with something mythos) [More Robert E. Howard than Lovecraft, but he was a good friend of Lovecrafts and wrote some very Mythos-y stories, check out the collection Black Caan for examples.]
- Ravager [Howard]
Drow of the Underdark (Based only on names)
- Insidious Corruptor
Heroes of Horror (names again), most of them
- Tainted Scholar
- Dread Witch
- Corrupt Avenger
Libris Mortis: Pretty much all of them
Lords of Madness: Pretty much all of them
Magic of Incarnum: All of the ones that involve merging Incarum into yourself.
Tome of Magic: All of them, binding dead shades to serve you. Particularly the binder.
Eberron Campaign Setting - Master Inquisitive (for investigators)
Races of Eberron
- Quori Nightmare
- Anything with Quori really
Champions of Ruin
- Black Blood Cultist (Degenerate humans, common in Lovecraft)
- Night Mask Deathbringer (Unable to function in sun, evil killers? Fiddle with the falavour a bit and make them degenerate)
Player's Guide to Faerûn
- Slime Lord
Serpent Kingdoms: Pretty much all of them
Of course, the Alienist class from Complete Arcane is specifically designed to be Lovecraftian in nature. They summon pseudonatural creatures. The D&D 3.5e version isn't OGL but here's a Pathfinder conversion that gets the general idea across. There are similar ideas in Gates of Firestorm Peak and the 3.0 Manual of the Planes, and the 2.0 Illithiad.
I'm also currently at a loss for classes that are directly inspired, but there are some things that could work well with a little reflavoring.
- Pretty much any psionic class. The connection "Far Realm - Cthulhu Mythos" isn't that far fetched (*cough* Illithids *cough*) and many aberrations that originate from the Far Realm have psionic abilities. Especially wilders could work well with their limited but rather powerful and volatile abilities.
- The generic Spellcaster class. This one works best for NPCs, since the variant generic classes are a bit weaker than the normal PC classes. However, since the flavor of the spellcaster class is completely open it could easily be molded into a cult ritualist or somesuch, especially since the spellcaster can learn spells (like a sorcerer) from the cleric, druid and wizard lists.
I don't think there are any others to be honest. The closest you will get is the Lords of Madness supplemental book.