Undead Familiar

When a wizard is directly to blame for his familiar's death, the betrayed bond can curdle into this horror. It resembles its living self, swollen and decaying, with missing eyes or ears and its death wounds gaping and infected. It moves with a corpse's stiffness, reeks of rot, and its eyes burn with animal fury.

It never speaks, but sends a ceaseless telepathic wail into its old master's mind that keeps him from sleeping, ruins his spellcasting, and has broken the minds of several mages.

It ignores everyone but its former master, fighting others only if blocked or attacked, using the attacks it had in life. Anyone it wounds must save vs. poison or catch a crippling disease of the sort cure disease treats; the old master saves at -4.

Reaching the wizard, it tries to meet his eyes. If it does, its dying agony and the shock of betrayal pour through their old link. He must save vs. spell: success still forces a fear check, failure a horror check, and a natural 1 adds a madness check. No one else is affected by this gaze.

Its unlife is fueled by the wizard's guilt, not the Negative Material Plane, so it shares few undead weaknesses. It cannot be turned and shrugs off holy water and holy symbols. It is immune to sleep, charm, hold and cold spells, to poison, paralyzation and disease, and to nonmagical weapons.

Reduced to 0 hit points it seems to die, but like a revenant it is relentless; even burning the body fails, and within a fortnight it returns from the mists. If it kills its master, he rises as a ghoul and the familiar finally dies.

Revenge is its only purpose, and only the wizard's death ends it. If he flees the misty dread realm, the creature loses interest and stalks the nearest other wizard, who is safe from its gaze and can be rid of it permanently just by killing it. Should the original master ever return to the realm, the wronged beast rises again.

It eats nothing, needs nothing and yields nothing of value.