Jun Kasai
In 2005, Isami ended his freelancing days, when he signed a contract with the Union Pro Wrestling promotion. Through Union Pro's working relationship with the Big Japan Pro Wrestling (BJW) promotion, Isami also made appearances for BJW, where he started a storyline with Jaki Numazawa and Mad Man Pondo, which led to him evolving his mixed martial arts-based wrestling style into a more deathmatch-based style. He was trained in the deathmatch style by Numazawa and Jun Kasai at their BJW affiliated School of Death training school. He made his deathmatch debut in 2006 and has retained the style ever since. In the deathmatch circles, Isami found himself a generational rival in Yuko Miyamoto.