Witch Slaves are a fictional species created by Nov on the website Mythical Creatures and Beasts.
Witch Slaves are dead trolls whom a witch would turn into undead minions bound to her will, through a ritual that had to be performed on top of a mountain. Bound to their creator's will, Witch Slaves would return to their grave after the witch who'd created them died. The process of their creation was discovered by a magician working for King Arthur, who posed as a necromancer to spy on a famous witch. Unfortunately, the witch unmasked him and killed him. In retaliation, the witch and other creators of Witch Slaves lent their creations to Prince Mordred as part of the army he used to finally vanquish King Arthur and take over Britain.