Unlike Akiyuki, Furuichi is more cynical and serious, although he is playful enough to bet with Haru on whether Akiyuki will be late or not.
After the sucide bombing that led Akiyuki to be taken away by Nakiami in order for him to control his new Xam'd powers, and deaths due to the battle between Northern and Southern Government causes destruction and deaths of his friends in Sentan Island, he eventually becomes a bitter individual that despises Humanforms (as the attacking Humanforms cause most of the damage), no matter if they were once good people or even a Xam'd. This hatred has developed since he killed a Giant Green Xam'd in cold blood even though Haru told him that she was pregnant. This worsens when he reunites with Akiyuki and discovered that he became a Xam'd, he tried to killed him against Haru's protests, only to be foiled by Raigyo.
After his battle with Akiyuki and subsequent arrest by Sentan Island military police, Furuichi escapes the truck he was being transported in. He proceeds to a small shop run by an elderly lady, where he orders three drinks, one for himself, one for his "beloved" Haru, and one for Akiyuki. Before the drinks are brought to him, he is once again surrounded by the military police. As they attempt to arrest him, he comments that he may be better off disappearing in both life and form - he then transforms his arm into Xam'd form, and decapitates himself.