Shawn the Shy Guy - When confronted with a threat, he mostly cowers. But when it counts, he can dig down deep and find his courage. He is very witty and loves to crack a joke, especially in the face of danger. Otherwise he might pass out. He used to be part of Bowser's army, but he left due to poor wages and bad condition. He felt he didn't belong anyway, because he was good at heart.
Weapon-
Shawn's mask can be used to give him a robotic exoskeleton. It adapts, so he could make a weapon of choice be created on his arm. It could also protect him as a safety bubble. He calls it "Hidden Fury".
Semblance-
Upon entering the world of Remnant, he gained a strange semblance that allows him to grow 6x his original size when he gets really angry. This, obviously, helps the team out greatly when shows of extreme strength are needed. And Hidden Fury, his mask/weapon can even adapt to that and make him even MORE powerful!