When the Thousand Sons arrived on their new homeworld after their escape from the Razing of Prospero, they found it to be uninhabited. Over the many thousands of years since that time, the Thousand Sons have brought so many captives back with them from raids out into the galaxy that the Planet of Sorcerers now possesses a sizeable non-Legionary population. From this population are drawn the Thrall Wizards.
Psychically or sorcerously inclined individuals are prized by the Thousand Sons, and many such mortals captured by them may find themselves bonded to a Thousand Son Sorcerer as an arcane assistant. Even the most ignorant humans can find a home in the ranks of the Thrall Wizards, as if a Sorcerer's Thrall Wizard Band is large enough, they can be apprenticed to a Thrall-Champion, in order to learn the simplest sorcerous tasks required by their masters, and provide supporting magic in battle. In this way, they can begin a career that may lead to becoming a fully fledged wizard in their own right, and perhaps further... for some Chaos Champions — and even Daemon Princes — of Tzeentch are said to have once been Thralls... as are many Chaos Spawn.
During the battles Thrall Wizards also act as a firepower troops of the Silver Towers of Tzeentch shooting magical energy bolts from the dozen of its towers and balconies to the enemies of Tzeentch.
- 1: Realm of Chaos: The Lost and the Damned ps. 268-269
- 2: Games Workshop Saved Archive Page (saved Jan 2012, last accessed 16 May 2019)