The horns are random, he has Kakuja Koukaku. He never really showed his Kakuja to anyone.
(Yeah I'll assume he's a guy, since there isn't any playable female characters in TF2. Not as I've seen.)
YOU ARE READING
Art Book.
RandomJust some of my drawings which I'm not very proud of. Also please excuse my ass quality camera., I'm saving money to buy a better phone okay-