Superalloy Blackluster is a large, bald man with round eyes and a defined jawline. He is very muscular, with a thick neck, large and well-defined pectoral and abdominal muscles and large, muscular arms.

He seems to be a vain person, as seen when he was sitting at a meeting with other S-Class heroes, he wondered whether everyone’s eyes were glued to his body and whether or not he was the shiniest person in the room.

(Source: One Punch-Man Wiki)