A Vampire/Phantom halfling, Thaddeus was adopted and raised by humans. Thaddeus did not know he was different from other humans until he was kidnapped and imprisoned by Declan Chase for The Order.

The revelation of the Lore was so traumatizing that he was catatonic for days until helped by his cellmates at the island prison, Regin the Radiant and Natalya the Dark Fey.

After escaping The Order with Regin, Natalya, Lothaire, Declan Chase, and Brandr the True, Thaddeus and his family were relocated to New Orleans. The Valkyrie and their allies took in Thaddeus for his training and education on the Lore.

Despite warnings from his friends, he still speaks with Lothaire and treats him like a friend.