In the darkness you make out a pile of treasure. Seated atop all this is a dessicated severed head, dusty, parchment-like skin pulled tight against the skull. The treasure gleams green in the arcane glow of the emeralds that line its mouth and stare out at you from its head. It does not move. Roll for Fortitude.
A lich is what happens when a wizard thinks living is for squares and makes itself into a skele-zombie to continue studying magic throughout eternity.
A demilich is what happens when a lich decides that plain ol' having a body's for squares and decides to encase its soul into a gem-studded bone. Normally a skull. They can be an evil sentient bejewelled rib if they feel like it.
So a demilich is even more dangerous than a regular lich, created by Gary Gygax in the infamous Tomb of Horrors adventure for the purpose of killing any player who thought D&D is just a game. In addition to all the spells that a normal lich would have, the demilich has a signature ability: trap the soul. It basically sucks the spirit out of your body (which instantly crumbles to ash) and traps it in one of its gems. It can wipe out a whole party in just over 20 seconds, combat time.
Don't worry, your soul won't be trapped inside the skull forever. The demilich will slowly eat you over the course of 24 hours.
