Quick answer — Kenichi Imaizumi worked on Kingdom Season 3 (Director), Kingdom Season 4 (Director), Kingdom Season 5 (Director) and 14 more anime.
Kenichi Imaizumi worked on Kingdom Season 3 (Director), Kingdom Season 4 (Director), Kingdom Season 5 (Director), Kingdom Season 6 (Director), Legend of the Galactic Heroes Gaiden: A Hundred Billion Stars (Animation Director), The Angel Next Door Spoils Me Rotten (Supervisor), REBORN! (Director), Legend of the Galactic Heroes: My Conquest Is the Sea of Stars (In-Between Animation) and 9 more.