Wistoria: Wand and Sword 11 (manga)

After a monstrous battle between two formidable Magia Vander, Will's fate is finally decided and he proceeds to his new faction. However, while those advancing to the Tower expect a straightforward orientation for their new assignments, they instead receive a grave mission: find the traitor who aided in the Terminalia attack. The Grim Generation must tread very carefully if they are to sniff out suspects in their respective factions…