Miguel was sent to rescue Aria from Kouga and the other saints. He was the first silver saint, with Johann, to fight against the protagonists.
He goes with Sonia and Johann to fight against Yuna (Miguel tracksherself), but Sonia asks to they don't disturb her own fighter against the bronze saint. But, when Sonia is called to go back to the Babel Tower, Miguel and Johann gets the fight. so, they protect Sonia from Souma (that arrived there). But, when Johann is defeated, Miguel tries fight, but they get away.
After, he goes to kill Kouga, a sinner saint, and Shun protect him; so, Shun is a traitor too, but knowing about the power of Shun, he gets away.... However, when Miguel remembers about the Shun's weak condition, try to kill him together Kouga. Shun uses his bit of power putting his life in danger, and destroy Miguel's cloth; but, Miguel continues to fight, and is defeated by Ryuho and Kouga.
After the war ends, Miguel goes to fight against Pallas, as a hero that know who is the true Athena.