It's sort of complicated. Akito was the original king of the Bloody Road, the fang king, whatever. Agito was an alter ego born as a result of Akito discovering that his brother's true intentions as to why he trained and had Akito become such an expert AT user. Agito and Akira were all bfflz and in the SWAT, and then blah blah something happened and Akira fought Agito for the Fang King regalia. I dunno if the titles are passed as the regalia is passed, but point is that at the point of the battle with Behemoth, Agito does not posess the Fang King's regalia, Akira does.