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

 * It's possible that Merlin was named after the wizard from the King Arthur legends, in which Merlin tutored the young Arthur before he became king and eventually became his advisor when Arthur became king of England.