Haven taken a hint from the Necromancers, the Cabal found that Bone does, indeed, retain it's tie to life. It is even useful in the ritual of of binding when enough power is at hand. Daemonic forces are summoned and controlled by use of this reagent.
Daemon Bones originally appeared in the single player Ultima games as a Sorcery reagent, and were to have been used in Ultima Online as a reagent for the (originally canceled) Necromancy system. Currently, daemon bone is a Mysticism reagent and can be found in Void Creatures of Ter Mur as a loot.
Bring 1,000 such bones (dropped by the monsters found in Doom) to Victoria the Sorceress. She will then summon a Bone Daemon, who drops a Golden Skull into your pack upon death. Bring this to Chyloth the Ferryman to access the deeper areas of the dungeon, where the Dark Fathers can be found. See the Daemon Bone Guide for how to collect Daemon Bone.