The undead focus spell allows the caster to cast spells through an undead being. The spells cast through the creature originates with it for all purposes, but the priest performs all casting activity, uses components, and so on. Thus, a hidden priest can avoid direct combat, casting spells through a selected undead creature. The distance between the priest and the undead being does not matter, but they must be on the same plane. Unless the caster has some way to see the undead or its surroundings, the spells cast through the creature are hurled from it blindly.
Spells to be cast through the undead creature can be chosen by the priest as needed. Up to one spell per round can be cast through the undead creature, until it is destroyed or until a maximum of one spell per level of the priest has been channeled through the focus. The spell ends after a maximum of 10 turns per caster level, even if the focus has not been exhausted.
While undead focus does not grant control of the undead creature by itself, other magics or powers that allow control or augmentation of the undead creature can be used without hampering this spell. If cast on undead creatures affected by revenance and/or undead battlemight, a dispel magic spell ends at most only one of these spells (choose which randomly).
The material component is a drop of the caster's blood.
Notes: Granted by the drow goddess Lolth.