Here is his character description, via IzanagiGames:
Keiichi (voiced by Hiroki Yasumoto) is a diehard fan still devoted to Hanaka despite her serving a prison sentence. He is easily excitable when it comes to Hanaka, but gentlemanly, and respectful of the distance between fan and pop star. He is taking part in the Yurukill Games to help Hanaka prove her innocence.
Previous trailers introduced Mass Murders team members Sengoku Shunju and Rina Azami; Binko; Death Dealing Duo team members Futa Yamada, Raita Yamada, and Kagura Kagutsuchi; Crafty Killers team members Gentoku Omuro and Izane Akegarasu; and Hanaka Ichirin.
Watch the trailer below.