(Internet at last!)
Didn't made many changes to the original idea and I guess I really like it now. 0__0

Lycaon, the same entity of the evil king of Arcadia awakens inside Cedric with only one purpose. To devour his mind and take over his body.
For a long time the king feed from Cedric's pain and hatred (which not only help him recover his strength but also made him stronger) and waited quietly for the right moment
However, Cedric's mind still fights back and yet Lycaon unleashes his power without having full control causing to them to transform into a mindless beast.