This will be a 3.5e compagin. The following books are kosher source material:
Player’s Handbook; Monster Manual; DM’s Handbook; Player’s Handbook 2; Complete Divine; Complete Arcane; Complete Warrior; Races of the Wild; Races of Destinty; and parts of the Eberron core book, as well as a few sections of Libris Mortis and the Dread Necromancer class from Heroes of Horror.
Other material will be okayed on a case-by-case basis.
Regarding alignment, you should be aware that any race or animal species has no fixed alignments, although there are strong tendencies (which match those given in the rulebooks). The only exception to this rule is dragons — they are still color coded for your convenience. Class restrictions on alignment may be loosened on a case-by-case basis. Good necromancers may exist, as can evil healers.
Because I think it makes sense, Dwarves and Warforged may also take Artificer as their favored class.
All characters aside from artificers with a craft magic item feat have a separate “pool” of XP for making magic items only, but at half the Artificer rate.
Critical failures (rolling a 1) may occur if rolling a 1 is still a failing roll. If it’s relevant, I’ll require you to roll again to confirm the crit-fail.
Various cheats and extreme exploits (i.e., the Locate City Bomb) are banned by the gods. If you think it’s an extreme exploit, and you want to try it, run it by me first.
Although summoning works as usual, the existence of the planes themselves is disputed because any spell that would take you there fails. Some people hypothesize that summoned creatures are temporary constructs of the caster, and that their attributes are determined by the caster’s expectations.
Psionics do not exist in this reality. Sorry.
There are also no dragonmarks (other than the Mynythe currency).
Characters will be starting at level 3, following a standard 25-point-buy. You also start with 3000 gp for spending on gear and such.
If you want to do the +2 LA for half-vampire, that’s fine — check Libris Mortis, or ask me for the details. For that template, add Light Sensitivity (Ex): In bright sunlight, or a daylight spell, half-vampires take a -2 penalty on attacks and other actions that require vision. Sunglasses are popular. In exchange, add 30 ft darkvision and a +2 to Fortitude saves against poison and disease.
I note that you can also be a +1 LA Necropolitan at game start, or give up a level later to become one (with appropriate background explanation and roleplay, respectively).
Otherwise, based on the half-vampire, here’s the quarter-vampire template, with +1 LA:
A quarter-vampire is the result of frequent unholy intermingling between the living and the dead, particularly in Life’s Edge, where half-vampires can live and love outside the repression of the Five Nations. In person, they seem almost normal — save for the pale color, and the cool skin, and a certain fondness for red colored liquids…
NOTE: I’m still developing this template. Let me know if you’d like to play it, but it seems unbalanced in either direction.
A quarter-vampire has all of the base creature’s attributes and special abilities, except as noted here.
Special Qualities: A quarter-vampire gains the special abilities noted below:
Resistance (Ex): A quarter-vampire has resistance to cold 5, as well as +2 to Fortitude saves against poison and disease.
Abilities: Increase from the base Dex +2, Cha +2.
Skills: Quarter-vampires have a +1 racial bonus on Bluff, Hide, Listen, Move Silently, and Spot checks. Otherwise, same as the base creature.
Feats: A quarter-vampire gains Improved Initiative, if the base creature doesn’t already have that feat.
There are no changes to a quarter-vampire’s possible bonus languages, speed, or favored class. There are no numerical penalties to being around running water, bright light, holy symbols, etc., though many quarter-vampires find them uncomfortable. (After all, at least one parent or grandparent-ish person tended to avoid them.)