Ruthless and cold-blooded, Jo is the head of a famous guild of Assassins in the Tojo Clan, the Amon Family. He is very prideful in his abilities, believing himself to be the strongest warrior in the world, but has faltered against only a few; Kiryu Kazuma, namely, whom he describes as his eternal rival. Driven to a point of obsession, Jo Amon has thankfully somewhat managed to quell his more "Whatever it takes" attitude, though he's still malevolent and intimidating. Cruel and confident, Jo is.