Mordred (Misry6)

"You're no Spartans, you're no knights, and you're no Trollhunters! In fact, you're not even children! You are NO ONE!"

- Mordred while battling Jim, Aja, and Douxie.

Mordred the Morbid is set to be the main antagonist of Fall of the Arcane Order: Before the Tales and the central antagonist of the Misry6 rewrite of Trollhunters: Rise of the Titans.

He is a warlock specialized in blood magic and shadow magic, the right-hand of Kronos, the Supreme Commander of the Arcane Order, and the archenemy of Douxie Casperan and Nari.

Official Biography
"The Cataclysmist — Mordred the Morbid was an evil being hailing from a parallel universe known as the Seventh Plane, the seventh universe to have been created. Disappointed that his subjects declared war against his despotism, Mordred wiped out his own universe, and eventually went to Kronos and became his top servant, the Daemon Knight. Mordred discovered the multiverse and became responsible for spreading chaos all across it, including the corruption of the Arcane Order, who are now under Mordred's whim to this very day."

Trivia

 * His headcanon voice is John Noble who voiced Unicron from Transformers: Prime.