Keitaro is an amiable young man who happens to be the Prime Minister of Begma, a title which is a king in all but name. He is, unfortunately, far better at being an artist than in the skills of kingship, as he's rather shy and retiring, rather than strong leadership material, though he does have a knack for making people like him once they get to know him. He's studied with King Tylor since he was little, but seems to have gotten a lot more from his training with Prince Miki and his friendship with Princess Mutsumi, as he's a skillful Trump Artist.
Keitaro is most noted for being a bit of a photography maniac, having made a trump camera which works everywhere, or so it seems. He loves photostickers and has huge folders full of them. He also practices trump sorcery and experiments with interesting Trump Artifacts, often in conjunction with Mutsumi. They're known to be close friends.
He has an endless feud with Kentaro; they hate each other. He is close to Mutsumi and is known to get along well with Prince Thoric and Prince Makoto. He has had a rather shaky relationship with Naru since the events of the Herald Crisis.
Since the Herald Crisis, Keitaro has become Prime Minister of Begma and married Princess Shinobu Minor. He is doing his best to lead his nation.
Shinobu Minor and Keitaro were nearly blown up by the recent disaster in Begma, but escaped thanks to quick action on the part of the Hemingway-hunting posse.