Can anyone point me to a (mostly?) compatible magic system/subsystem with a slightly darker flavor? I'm looking for something where arcane spells take a toll on the Spellcaster, or the player has the option to make some sort of sacrifice to cast stronger spells. Also interested in being able to reduce other caster's spell casting for the day. Think spells/abilities that drain spell levels from the target, etc.
Open to 3rd party material as well as any existing 3.5/pathfinder spells, feats, classes, etc.
Thanks!