Ichise is very quiet and rarely speaks. He has an odd tendency to go berserk at very inopportune times. Whenever something has angered him, he channels nearly all his energy in an effort to destroy whatever it is that has crossed him. Throughout the course the series, he becomes a little more open, but still remains fairly reserved unless someone directly asks him a question.
spoilerAfter one of his fights, he gets into some trouble with Aida, the man who runs the arena. He was rewarded with some cheap sex, but becomes slightly hostile during the love-making. Aida calls up Isshii, a member of Organ, to come and punish Ichise. He does so by lopping off Ichise's right arm. Afterwards, Ichise goes berserk and ends up getting his left leg cut off in similar fashion by Isshii.
He manages to get around with a crude crutch, but ends up giving up in despair after he continually has trouble with stairs. Oonishi, the leader of Organ, calls up Doc and tells her that Ichise might be a decent guinea pig for her research. With Doc's 'help', he gets a new Texhnolyzed arm and leg.
At first, he abhors his new limbs, but manages. He sees Isshii again and attempts to attack him, but is put down by Isshii's men. He is thrown into the sewers, but manages to escape with the help of Ran. He then spends some time practicing with his Texhnolyze to get the hang of it. He locates Isshii later and manages to beat the shit out of him.
He then walks around with Ran for awhile. He runs into Shinji, leader of Lakan, who invites him to Lakan's headquarters. There, he practices the sensitivity of his Texhnolyze. He then leaves and shows up again in the middle of a large confrontation between Organ, the Alliance, and Lakan, where he inadvertantly sets off the spark that starts the war. At the end of the battle, Oonishi brings him along where he eventually stops Yoshii from destroying Lux.
Oonishi then includes him as a temporary member of Organ and assigns him to work under Kohagura. He works alongside Touyama and captures Sakizaki, who stops Mizuno's half-assed plans of taking over Lux. He also discovers the people who framed his father and beats the shit out of them.
After that, he becomes an official member of Organ. He helps uncover Gabe's factory that is mass-producing weapons and saves Oonishi's life when Mizuno tries to kill him. At that point, Ran tells him his future wherein he will destroy everyone and will end up all alone in the end. After getting some nice upgrades to his Texhnolyze courtesy of Doc, he helps Kohagura and Sonada escape from Tsujinaka's men, then kills Tsujinaka under Kohagura's orders. Afterwards, he is assigned to protect Goto when the Shapes make their appearance. He saves Goto from being killed and helps Organ fight back against the Shapes.
Oonishi then asks him to go and find Doc to help the wounded. After finally getting her to agree to come out, she tries to pull some lovey-dovey stuff on him and says that they should just go to Gabe and spend their lives together because the people of Lux are doomed. They then see Ran in the center of Lux and run into Oonishi and Shinji at the train station. Oonishi asks him to go with Doc to warn the people of Kanno's plan, but he refuses because he's worried about Ran. Oonishi tells him that his debt has been repaid so he is free to decide for himself what he will do.
He heads to the upper world with Doc. Upon getting there, he realizes that the Class is no different than Lux - everyone is just sitting around and waiting for death. He realizes the trip was pointless and heads back to Lux. Before he can get there, he runs into Touyama and is forced in a katana duel, which he wins. He also meets with his deceased father and apologizes for how badly he had thought of him through the years when his hatred should have been placed on the thugs that framed him.
He eventually makes it back to Lux only to find out that no Texhnolyze works anymore. He meets Goto who tells him that it's pointless to head back into the city. He goes there, anyway. He meets with Ran and tells her that he wants to bring her to the upper world where there is no fighting. He tells her that he believes he is her guardian angel and that's why he came back.
He watches as Oonishi is annihilated by the men of Lux, at which point he goes berserker and beats the hell out of them all as he regains partial control of his Texhnolyze with Doc's help. He heads for the Opera House to find Kanno and, consequently, Ran. When he asks about Ran, he gets a long-winded story about Kanno's motives.
He eventually finds out that Ran has been Shaped and that her 'spirit' has been killed and she basically has no more consciousness. He is mighty miffed that Kanno did this and, despite knowing that Kanno is the life-blood of the Lux, lops his head of with a powerful fist to the face.
He returns what's left of Ran to the place where the Elder's body was finally laid to rest and finds exile in a building on the outskirts of the city. He glances over the city one last time, then rolls over to his side and watches his Texhnolyze arm play a crude, line-art of Ran's flower. He closes his eyes, smiles, and the world around him, and eventually he, fades away.