Eugene was a nuclear scientist and CEO of a conglomerate, whose company’s front is chemical energy development, but actually has military intervention in third world countries where they also perform human experiments. Since Frosti is always a target for assassination, he hires elite Kairoushu bodyguards during public appearances to protect him, his last being Yoite and Yukimi. His assistant is Nowake.
Eugene's assassination was a mission ordered out by Yae Oda to Tobari and others, in exchange of Togakushi's kinjutsu - Izuna Shingan.
In the parking lot scuffle, Kouichi was the one that shot him when Tobari couldn't. His death was blamed on his own assistant.