Originally named Kawajiri, this orphan was raised by an elderly couple deep within a forest, where he cared for his two adoptive younger sisters, Yakumo and Nikaido. At sixteen, his powerful magic led to recruitment for the Devil Exam. Leaving his family behind, he became a Devil, adopting the name "Asu" and developing a brutally honest demeanor, a taste for luxury, and habits like consuming greasy food. A shift occurred when Nikaido's time-travel magic altered their shared past, creating a timeline where he never knew his adoptive family. Raised instead in a Devil church orphanage, he still attempted the Devil Exam. During his transformation, Magic Users attacked him to exploit his rare magic. A young Nikaido intervened, saving him. After completing his devil transformation, he took her in. Recognizing the danger her time magic posed to her from the omniscient Devil ruler Chidaruma, he hid her existence, trained her in combat, provided her with a power-enhancing mask, and sent her to live safely in Hole. Despite separation, they maintained contact, with Nikaido visiting and treating him as an older brother. Later, Nikaido sought his help investigating Risu, a figure linked to Kaiman's past. Though unable to provide information, he expressed concern for her safety, especially after sensing her kidnapping by the crime boss En, who forcibly made her his magical partner. Unable to intervene directly without alerting Chidaruma, he facilitated Kaiman's escape from Hell to rescue her. He then created a Nikaido clone from another character, Chota, to aid her and Kaiman's escape from En. Confronting Chidaruma over hiding Nikaido resulted in brutal punishment. Chidaruma used a creature called Store to dismember his Devil body, stripping him of his devilhood and reducing him back to his original Magic User form, Kawajiri. Severely injured, he attempted to rescue Nikaido from En again but arrived too late, only managing to save Kaiman before collapsing. Recovering with the help of a masked man named Aikawa, he teleported to En's mansion to retrieve Nikaido, finding her physically deteriorated due to resisting the partnership contract. He took her to his home and trained her to control her time magic, using methods reminiscent of his Devil Exam, like weighted armor. He also repurchased his severed Devil body parts to cook meals, unsettling Nikaido. Assisting Nikaido in researching her magic, he disguised them as Cross-Eyes to infiltrate En's mansion. There, they retrieved a book on time magic and encountered Risu and Aikawa. They later lived together with Risu, though he frequently teased Risu about his poverty, creating tension. He supported Nikaido as she perfected her time magic, culminating in a magic time machine box that destroyed his house. They traveled to Hole, using the box to rewrite her past by saving Yakumo from drowning. Returning to the present revealed the limitations of her magic, including the finite "bullets" in her time device. Nikaido's new Devil abilities made her cooking dangerously potent. He and Risu became the first to experience her overpowering gyozas. While selling these gyozas at a department store, they encountered a blackout and a zombie invasion. Attempting to teleport them to safety, his magic failed due to the store's location in a magic-nullifying area, resulting in the loss of his fingers and his capture. Rescued by a Devil named GuraGura, he was brought before Chidaruma. Chidaruma expressed regret over stripping his devilhood and tasked him with cooking gyozas for a Devil party, providing him with a chef outfit and workspace.