In the anime Kouse is an orphan who is trained to be a Jinki pilot and cold-blooded killer. He was sent to "test" Aoba in the anime.
In the manga however, Kouse was not related to Shizuka in any way, and although he was still an orphan, he was a member of the military, and worked with Shouse (who did not appear in the anime) to stop the autonomous actions of "Angel" in Venezuela. In either case, Aoba befriends him and they work together to stop Kokushou in the manga. In the anime, he would be shot by Shizuka and although he was wounded he does not die from it. Kouse pilots with Shouse, the Jinki "Schneigar CX". In J:E, Kouse is a Jinki test-pilot as well as regular member of "Angel". In what little appearances he made in J:E, he was last seen piloting the prototype flight/transformation-capable Jinki called D-77 Masamune.-Wikipedia