Fiend Cabalist (3.5e Feat)
From D&D Wiki
You were trained in the mystic arts by a powerful fiend, and your magical power stems from a dark source.
Prerequisite: Caster level 1
Benefit: You gain Knowledge (The Planes) as a class skill, all of your spells gain the [Evil] subtype, and spells you cast and magic items you create radiate an evil aura equal to the strength of their normal magical aura. Any spells you cast that already have the Evil subtype gain a +4 caster level.
Special: This feat can only be taken at 1st level.