Sou is extremely tall individual who appears to be wearing diving suit. Usually he wears white cloak on top of suit.
Sou dont speak much. He prefers to speak in one word short sentences.
Nothing is known about Sou prior entering Area D island.
Sou appears with Mist and Lizard in front of Owls Eye to get further instructions about capturing Jin alive. While Mist interrogates Zero, Sou appears to be holding hand over Zero's head. After Zero kills Mist, Sou enrages and is seen to be following him but as soon as Sou sees Jin, he changes his priority target. As Sou charges towards Jin, he is stopped by Mariko. Then Zero uses this situation and cuts Sou's head thus activating his ability. True form Sou puts continues to charge towards unconscious Jin while devouring fellow Übermensch Union in his way. As he changes his target to Satoru Ida, Sou falls into Jin trap when Satoru activates his ability and electrocutes Sou. He explodes into black dense substance pieces scattered across hall.