Kankou, better known as Umibouzu, is Kagura and Kamui's father and one of the last surviving Yato clan members. He fights with an umbrella like his daughter, though he's more than capable of holding his own—he's actually one of the few people who can match Kagura in a fight. He's got a cybernetic arm, which comes in handy.
He first shows up when an alien invades the Terminal, teaming up with the Yorozuya to take it down. After that, he takes off to hunt aliens across the galaxy, staying in touch mainly through letters. In one message, he casually suggests they should probably get rid of Sadaharu too, since he's also technically a monster—a suggestion the crew was not thrilled about.
At some point, Kankou gets recruited to lead the "Principality." In the anime, his recruiter is basically a Char Aznable clone, while the manga goes with a Darth Vader lookalike instead. He also inexplicably ended up in a hair growth shampoo commercial, which was apparently so long that even the Yorozuya felt the need to complain about it.
Creator Hideaki Sorachi confirmed in a volume 57 Q&A that Umibouzu's actual name is Kankou.
Content compiled by AnimeList.moe from publicly available sources.
