Mustain plays the guitar and is know by other teams to be a playboy. He was the one who found a unconcious Melrose when the Dark Air first appeared. Mustain is currently a traveling companion of Melrose, Shenandoah, and Forest Freelander.
Mustain has past-shoulder length black hair which he normally ties up. Mustain also normally wears glasses, though he takes them off when in a battle. Most of the time, he wears a long coat. When he goes to town, Mustain sometimes disguises himself in outfits ranging from just a fake mustache to a full mariachi outfit.
Guitar: Mustain can use his guitar to provide enhancement buffs to his teammates. Apparently, he is quite skilled, as he can use both offensive and defensive buffs at the same time, making him the level of a "grandmaster"