Shira has worked as a mercenary since the age of sixteen. Taken from death row, he was recruited by Habaki to work within the Mugai-ryu.
Shira is a sadist (often sexual). He enjoys torturing and raping women concurrently (and sometimes young boys), and will never kill a woman without attempting to catch her alive first.
Among the many he has killed, Shira notably raped and murdered O-Ren, the prostitute girlfriend of Ittou-Ryu member Taito Magatsu, leaving Magatsu with a personal vendetta against him. He attempted to kill another prostitute who was paid to disguise herself as Anotsu Kagehisa (posing as a woman) and maimed her, cutting off her leg and slicing her breast while assaulting her. He shows his sadistic side to Rin after killing and eating a dog she had befriended, and later attacking the said prostitute in front of her. He also punches Rin in the face when she tries to stop him.
Magatsu and Manji team up unexpectedly after awhile and confront Shira for the first time since his Mugai-Ryu days. He had since carved the bones of his missing arm into claws. Magatsu tells Manji to stay out of the fight, and he and Shira fight a long battle, ending with Shira hanging off a cliff. Magatsu cuts his remaining hand off, making him fall and is then presumed dead.
Shira had been imprisoned after his fall and experimented on. In prison he met Renzo, the young teenager whom Rin had befriended during a festival in volume 4. Shira abused Renzo and made the boy work for him. Shira was one of few subjects to survive the immortal experimentation. After this process, however, Shira lost the ability to feel any pain.
Later, he manages to kidnap Rin in an intricate plot to fight Manji, stripping most of her clothing and tying her wrists to a dock, suspending her body in a freezing pond. He also attempts to rape and cut Meguro, but Magatsu saves her. During his fight with Manji and Magatsu, Shira alludes that he sexually assaulted Rin as he had with O-Ren, and killed them, leaving both Manji and Magatsu in insatiable rage. It is never shown if Shira really assaulted Rin or just said he did to enrage Manji.
With Manji's limited help, Magatsu is finally able to permanently subdue Shira, leaving him on the verge of death shortly before wild dogs finish him off.
Relationships to other charactersEdit
Magatsu Taito: Since Shira murdered his would-be girlfriend, O-Ren, Magatsu has sought to avenge her death by killing Shira. He presumably wins in the graphic novel "Autumn Frost". When Shira resurfaces, Magatsu knows his limitations, but saves Meguro from Shira's clutches after a bout of wavering whether to do so or not. Magatsu and Manji finally team up to (mostly) finish Shira off for good.
Manji: Shira delights in fighting Manji because of his immortality. Manji, upon their first meeting, says he doesn't trust Shira. After Manji comes upon Rin and Shira (who is attacking and maiming a prostitute in the road) Manji briefly fights him. Manji and Magatsu Taito team up later, and Manji leaves Magatsu and Shira alone to fight. They meet once again at the end of the Prison Arc, and finally for the last time after Shira kidnaps Rin in order to initiate one more fight with Manji.
Renzo Kawakami: Renzo met Shira when they were imprisoned together. Shira raped him and the unnamed female inmate (whom he subsequently murdered in the process) and, after realizing Renzo was still alive, made the boy his personal servant for living and sexual needs. Eventually Renzo develops an attachment to Shira, and has trouble leaving his side. In Shira's last moments, Renzo is the only person watching him die, and Shira spouts some of advice to Renzo.
Mugai-Ryu Members: Shira is never close to any of the other Mugai-Ryu members. It is alluded that the members know Shira has a sadistic streak, but even they don't seem to realize to what extent. Shira also helps Tamasaki and his companions easily subdue and kidnap Hyakurin in "Beasts" (by telling Tamasaki where she is and scouting ahead of time for Giichi).
Weapons and fighting skillEdit
Shira is one of the strongest and most tenacious fighters in the series. After losing one hand to Manji and the other to Magatsu, he is still formidable enough that their combined strength is necessary to finish him off for good. Against ordinary fighters, Shira's overwhelming strength allows him to toy with his opponents before killing them, inflicting as much pain as possible to satisfy his sadism. He also seems to have little fear of death in any of his fights.
Initially, Shira fights with a serrated kantana that he uses to torture his adversaries. His immense strength allows him to wield the weapon very effectively with one hand. Later, after losing both of his hands, he fights with the sharpened bones protruding out of each forearm.
Shira starts out with black hair, but after losing his arm and carving his bones into blades, his hair turns white.