Hiroto Sakurai is a young man who becomes a participant in the Gantz program following his death during a catastrophic event. He is originally brought into the Gantz room after being killed in the Shinjuku massacre, a violent incident that serves as the entry point for several characters into the deadly game. His online handle and nickname given by the Gantz system is Cherry, a name that causes him visible embarrassment when its meaning is questioned by others.

Before his involvement with Gantz, Sakurai’s background is marked by profound suffering. He was a student at a pharmacy college where he endured severe and relentless bullying from classmates, which included sexual abuse and humiliation. This torment drove him to contemplate suicide, and he posted his intentions online. Rather than receiving help, he was met with cruel mockery from numerous netizens encouraging him to end his life. It was in this dark period that he was contacted by Kenzo Sakata, a man who claimed he could teach Sakurai to unlock latent psychic powers. Sakata encouraged Sakurai to use these newfound abilities to kill his abusers, which he did. However, the act brought him no peace, and he immediately regretted becoming a murderer, a guilt that would shape his subsequent actions.

In terms of personality, Sakurai is initially portrayed as a timid and deeply vulnerable individual, a product of the relentless abuse he suffered. He is, however, not without a strong moral core. After killing his bullies, he is consumed by regret and a powerful desire for redemption. This motivation drives him to partner with Sakata to hunt down murderers using his psychic powers. When he witnesses the Shinjuku massacre, he does not hesitate, insisting that he and Sakata intervene to stop the killer. He sees this not just as a heroic act, but as a crucial opportunity to atone for his own past sins, arguing that they can redeem themselves by stopping the perpetrator. This sense of justice and redemption remains a key part of his character even as the circumstances around him grow more desperate.

A pivotal relationship in his life is with a girl he met online named Tonkotsu. At a time when most people were telling him to die, Tonkotsu was the only one who desperately pleaded with him not to commit suicide and offered him friendship. She later becomes his girlfriend and represents the most important emotional anchor in his life. His other critical relationship is with his mentor, Kenzo Sakata, who not only taught him to use his powers but also acts as a supportive and guiding figure. Within the Gantz team, he develops a strong respect for Kei Kurono, admiring his bravery and leadership, which leads to Sakurai placing his full trust in him.

Throughout the story, Hiroto Sakurai undergoes a dramatic and tragic development. He is a phenomenal learner who masters his psychic abilities with remarkable speed. During his initial missions, he fights alongside the Tokyo team, using his powers and Gantz weaponry to survive. At one point, he is killed in battle against a powerful alien known as the Flame Oni, only to be revived by his teacher, Sakata, at great personal cost. The narrative takes a devastating turn when Tonkotsu is killed during an alien invasion of Earth. Her death completely shatters his psyche, transforming him from a remorseful young man seeking redemption into a grief-stricken and vengeful force of destruction. Overwhelmed by loss, he begins roaming the ruined city, swearing revenge and slaughtering any aliens he encounters. He descends into a state of near-madness, haunted by hallucinations of Tonkotsu and Sakata who plead with him to stop his killing spree, but he rejects their voices and continues his rampage, even turning his powers on seemingly innocent alien civilians. This mental and emotional unraveling represents the tragic culmination of his character arc, where his immense power becomes a vehicle for his own destruction as much as for his enemies.

Hiroto Sakurai is distinguished by his phenomenal psychic abilities, which set him apart from other hunters. By the final arc of the story, he is arguably the most powerful human character in the series. His abilities are primarily telekinetic and expand to include a wide range of applications. He can generate powerful barriers to block energy attacks, phase objects and even his own body bomb out of his own head through solid matter, and teleport himself over short distances. His raw power becomes so immense that he is capable of ripping apart giant alien robots that tower over skyscrapers with relative ease. The strain of using such abilities is immense and was shown to cause physical deterioration like nosebleeds and organ failure in his teacher, but the regenerative properties of Gantz's teleportation technology seemed to mitigate these effects in Sakurai, allowing his power to grow to extraordinary levels without the same physical cost. Despite these god-like abilities, his physical body remains human and fragile; he relies entirely on his psychic powers for defense and offense, leaving him vulnerable if they are circumvented. His journey ends during the final battle against the alien mothership, where, after being critically wounded and losing most of his body, he experiences a final hallucination of Tonkotsu and Sakata. In his last moments, he uses the last of his strength to save two alien children from falling debris, finding a final, tragic redemption before he dies.