Magus is the leader of the fiend army in 600 AD during their campaign to overthrow Guardia. During their second neccessary visit to the time era, the party with Frog confront and fight Magus in his keep, where they discover him attempting to summon Lavos. When he is defeated, he loses control of Lavos, plunging both him and the party into an unstable gate which take the party to 65000 BC and himself to 12000 BC. During this time he masquerades as a prophet, attempting to get the Queen to summon Lavos. When the party arrive in 12000 BC, he orders their arrest. After they are freed by Schala, he catches them, but spares them on the condition that Schala seals the gate to prevent their return. When the queen summons Lavos, he is in the group who oversee the arrival, at which point he reveals himself and attacks Lavos. The party attack Lavos. Following their possible defeat, Crono is killed and the remaining party members and Magus escape with the aid of Schala. Magus is next seen after that on Cape Peak, where the party confront him. He reveals his true identity as Janus, and that he was summoning Lavos to get revenge. He challenges them to a fight. If the party refuse to fight, he joins the party, but if they fight and defeat him, they will get Schala's Amulet. If he joins the party, he will tell them how to revive Crono.
Fight against the DevourerEdit
If the party fight against the Devourer, Magus is seen beforehand as the Prophet. He attempts to free Schala and attacks the Devourer. He is defeated easily though.