Summon Spectral Death

This evil spell summons a spectral death, a billowing cloud creature of negative energy, to find and slay a creature described to it by the caster. (It cannot otherwise be commanded to fight for the caster.) When it is summoned, the priest must have cast a protection from evil spell, be within a protective circle, or have a special item used to control the spectral death. Otherwise, it attempts to slay its summoner and return from whence it came.

The spectral death returns to its own plane whenever the spell lapses, its mission is fulfilled, it is banished (by means of abjure, dispel evil, holy word, or some similar method), or the priest is slain. If the spectral death cannot complete its mission within 1 day per caster level, and none of the foregoing have occurred, it relentlessly tracks its summoner. If it confronts its summoner, it attacks in a rage, striking as a 20 Hit Die creature and inflicting 3d6 points of damage with each successful hit.

When raging, the spectral death is 50% resistant to any attempt by the summoner to banish it back to its home plane (the quasielemental Plane of Vacuum). This is adjusted by 5% per level (or Hit Die) difference. The spectral death has 20 Hit Dice for this purpose, thus its resistance to a 15th level caster is 75%.