Merlin

Merlin was the wizard who was in a party set out to kill the Monster Lord Alice XV. Along with Marcellus, Lazarus, and Karen, he realized Alice XV's wishes for coexistence and were preparing to spread her dreams.

However, a young Alice XVI spotted her deceased mother and killed Merlin and Karen out of blind rage, prompting Marcellus and Lazarus to start Ilias Kreuz.

Trivia
In the Arthurian legend, Merlin was the mentor of King Arthur and was his tutor when the king was a young boy.