He is extremely large, both in height and weight, standing 6'9" and weighing almost 300 pounds in muscle mass. He has pale skin and black, oily hair that is kept in messy strands. Strangely enough, he has no iris in his left eye and the right one is covered by a red node that runs down his cheek and onto his right arm. His nose is flattened, which Pandora jokes that a punch to the face caused it. His teeth are sharp, and his jaw is fixed in an underbite. He has shackles on his wrists, suggesting that he broke out of a prison before going under service of Hephaestus. He is extremely well-built and wears tight, black leather suspenders, pants, and shoes that can expand to any size to fit his own.
Distant and unwelcoming, Baldr's only real friend is Pandora, who is the daughter of his master, Hephaestus. He does anything she says, and even doesn't retaliate when her jokes and pranks bother him. To this end, he is far from simple muscle, as he has revealed on numerous occasions that he is capable of solving riddles that no one else in the party is capable of. He is somewhat fearful of Ares, not for his fighting ability, but because he is the only one capable of unleashing Baldr's inner beast, which causes him to fight with an uncontrollable rage. The only one who is able to help him out of this state is Pandora.