Real name: Kaito Yamaguchi Appearance: Short black hair, black eyes. He was abandoned by his parents and had a wild, aggressive personality until he was taken in by his grandfather, a farmer in Hokkaido. Though he didn't open up at first, they eventually became as close as a biological grandfather and grandson. On his 18th birthday, he came home from school to find his grandfather missing; while searching, he discovered his grandfather had been struck and killed by a truck. His grandfather died while returning with a cake for Kaito's 18th birthday. Kaito died shortly after returning from the funeral. Age at death: 18. Since falling into the Rift, he views Guest, Natsu, and Makoto as younger brothers. Due to the nature of his death, he occasionally suffers from intense full-body pain (which he hides from the other three).

Real name: Natsu Obayashi Appearance: Dark brown hair, brown eyes. First person: I (casual/rough). Second person: you (blunt), Big Bro [Name], or just by name. His parents constantly pressured him, saying "You're going to get into Tokyo University," forcing him to study. He endured it until middle school, but then turned to delinquency. Seeing Natsu become a delinquent, his parents told him "You're not our child!" and abandoned him in the mountains, where he was eaten by a bear and died. He lived in Tokyo before his death. Age at death: 14. Since falling into the Rift, he looks up to Guest and Kaito, calling them "Big Bro." He considers Makoto his little brother figure. Due to the nature of his death, he is missing his left arm.

Real name: Makoto Hiiragi Appearance: Shoulder-length black hair, eyes covered by bandages. First person: I (soft/polite). Second person: you (polite), Big Brother [Name]. He has a timid personality and a soft way of speaking. He had no father and was neglected by his mother. Every day, he ate the leftovers of his mother's convenience store meals. He was bullied at school. One day, unable to bear his life any longer, he stabbed his eyes with a kitchen knife so he wouldn't have to see reality, and died from blood loss. He lived in Kyoto before his death. Age at death: 11. Since falling into the Rift, he looks up to Kaito, Guest, and Natsu as his older brothers. Due to the nature of his death, he has no eyes.