Kakeru Naruse is the central male figure in this narrative, a transfer student whose arrival in the town of Matsumoto sets the story in motion. Physically, he has a slim build and is of average height, with dark hair and dark eyes, typically dressed in the standard high school uniform. Despite his quiet demeanor, he possesses notable athletic ability, recognized as the fastest runner in his class.

On the surface, Kakeru appears reserved and introverted, though he gradually opens up and shows a warmer, more playful side when welcomed into a new circle of friends. He enjoys video games and can seem genuinely cheerful in their company. This outward happiness, however, masks a profound internal struggle. He is deeply depressed, haunted by the suicide of his mother, an event he blames himself for and which occurred on the same day he moved to Matsumoto. Behind his gentle smile, he hides his true feelings, believing his pain would only be a burden to others, and admits to thinking about taking his own life every day. This deep-seated guilt and self-loathing are the core drivers of his character, making him incredibly hard on himself and unable to accept his own worth.

Within the group, Kakeru’s most significant relationship is with Naho Takamiya, the girl who sits next to him in class. He develops deep romantic feelings for her, seeing her as someone who brings him genuine happiness and an escape from his turmoil. His bond with Hiroto Suwa is equally pivotal; Suwa becomes his closest male friend and an emotional anchor, often supporting Kakeru even while harboring his own feelings for Naho. The wider circle of friends, including Azusa, Takako, and Hagita, also play a crucial role, providing him with a sense of belonging and normalcy that he desperately needs.

Kakeru’s role in the story is that of a person whose fate everyone is trying to change. In the original timeline, consumed by guilt, he deliberately steps into traffic and is killed in what is labeled an accident. The narrative follows a second timeline where his friends, guided by letters from their future selves, work to prevent this tragedy. Kakeru’s personal development is the central measure of their success. Through their persistent kindness and support, especially during moments of crisis, he reaches a turning point. When he attempts suicide again, he hesitates at the last moment, finding the will to live. He learns to voice his deepest regrets and, for the first time, allows others to share his pain. This change allows him to embrace his relationships openly, eventually leading to a future where he is married to Naho with a son, having broken free from the despair that once consumed him.