Demoncall

Book of Vile Darkness 3.5
By Monte Cook

Divination [Evil]

Level: Blackguard 2, Demonic 2,
Components: V, S, M
Casting Time: 1 action
Range: Personal
Target: Caster
Duration: Instantaneous

The caster taps into the forbidden knowledge of demons, giving her a +10 profane bonus on any one check (made immediately) involving Knowledge (arcana), Knowledge (the planes), or Knowledge (religion).