Sorcerous Sea Skull Swarm

The act of creating a demilich sometimes goes horribly awry, leaving behind a shattered remnant of a once-mighty spellcaster constantly leaking eldritch energies. The ruined spirit animates a cloud of debased copies of itself, glittering with cracked crystals in crude imitation, and it hungers constantly for the magical energies denied it in its corrupted immortality.

Some of the spellcaster's personality remains in the swarm, albeit usually unnaturally split between the skulls. As a consequence, the skulls argue among themselves as warring parts of the personality clamor to be heard, resulting in the swarm's fractious, inconstant attitude.

A skull swarm is composed of reanimated masses of craniums and jawbones, forming a terrifying avalanche of undead fury. Most skull swarms are mindless, though some retain a vestige of wit, awareness, and even magical talents from life, culminating in a highly intelligent swarm mind.