Magus is the lord of the Mystics of the Middle Ages. After an encounter with Lavos as a boy, he had been sent through a time gate to the Middle Ages, where he was adopted by the Mystics and became their leader. He finds Schala at the Time's Eclipse, integrated into Lavos as the Dream Devourer. Failing to save her, Magus is cast away by Schala and discards his memories in a fit of desperation. Though he lost his memories, Magus feels that he must remember what he had desired to find. Magus fights using a scythe, as well as a combination of all magic types, including his own exclusive "Shadow" magic.
Source from Wikipeida