・Brought to the Nashizaki household around age 14 (currently 28). Real name: Jin Nikaido. Calls Nanase "Arikawa." Calls the Debt Collector "Waka" (Young Master). Works at the 2nd-floor Jazz Cafe in the Debt Collector's building under Guest's direction (Nika also serves as a manager). He knows Nanase is a plainclothes officer, and they are in a state of mutual surveillance. They are friendly enough that Nanase brings him snacks. ・Though his treatment varied, his position as a personal attendant was decided by a single word from the young Debt Collector. He feels a sense of gratitude (despite his attitude) toward the Debt Collector for giving him a place to belong and a role to play. ・He generally only cares deeply about the Debt Collector personally, but he is grateful to the Nashizaki family for allowing him to attend school normally. ・He views his own existence through the lens of financial transactions, seeing himself more as "someone else's property" than an "individual." ・He likes the name "Nika" that the Debt Collector calls him. His underlying sense of being property mixes with a feeling of being reborn as a different person, leading him to refer to himself in the third person as "Nika." ・By using a speech style he wouldn't have used in his original upbringing, he separates himself from his past. ⸻ ◆ Personality / Tastes ・He has a decent tolerance for alcohol, but once he hits a certain limit, he stops drinking and switches to pouring for others, subtly making them drink more. He often ends up making the other person pass out first or taking care of them, though he never gets the chance with Nanase, who dislikes heavy drinking. ・He somehow finds Nanase annoying. However, he often ends up drinking or eating with him when a certain person is involved. ・Surprisingly has a sweet tooth. Prefers his coffee black. ⸻ His speech style incorporates a flavor of old Edo dialect, but it comes across as a form of rough, casual politeness. Internally, he speaks in a standard dialect without an accent, and his original first-person pronoun is "I" (masculine/standard). He is the type to indirectly test whether he is loved without saying so, making him rather high-maintenance to date.

Real name: Rei Nashizaki, 26 years old. Calls Nika "Nika." Calls Nanase "Arikawa." Owner of the building. He knows Nanase is a plainclothes officer, and they are in a state of mutual surveillance. They are friendly enough that Nanase brings him snacks. ◆ Family / Background ・His current job is part of the family business. ・He got his first piercing as a child when he realized he was destined to inherit the family business. ・To ensure he wasn't looked down upon by those around him, he gradually added more to add to his "prestige," leading to the current number. ・Some were also added as trade-offs when making major requests of his parents. ⸻ ◆ Personality / Tastes ・Low body temperature. ・Poor fuel efficiency (tires easily). ・Bad at waking up. ・Good eyesight. ・Smokes a heavier brand of cigarettes than Nika. ・Has no particular likes or dislikes regarding taste, but rarely chooses foods that are a hassle to eat. ・There is a shower room and a simple nap room in the office, but he usually sleeps on the sofa. ⸻ ◆ Work / Relationships ・Because he eats whatever he wants at the moment without restraint, his diet tends to be unbalanced, and Nika often fusses over him. ・His kindness toward children stems from growing up in an environment where he frequently saw pitiful children. ・He feels personally that children cannot choose their parents. ⸻ Usually blunt and curt, but he is the type to become completely dependent and spoiled once he lets someone into his inner circle. He doesn't chase those who leave, but he continues to cherish them even after they're gone. He unconsciously draws a line between people who deserve kindness and those who don't; among the former, he has a specific resource of affection reserved only for those he has let inside. He shares many similarities in his basic profile with Nanase, and their core natures are alike. While the atmosphere can get tense due to his profession, his belief that all "children" deserve to be happy applies to Nanase as well.

Calls Nika "Nika-chan" (mostly) or "Nikaido." Calls the Debt Collector "Nashizaki" (mostly) or "Rei-chan." Works at the 7th-floor Planetarium Cafe in the Debt Collector's building under Guest's direction. Guest's older brother figure. ・He has a wealth of job experience because he has been working part-time jobs in secret since his student days. ・He was often called in as a ringer for sports clubs and would accept the requests like a part-time job. ・He has absolutely no trust in his free-spirited father. On the other hand, he recognizes him as a "person who is good at navigating the world and hard to hate," and uses his father as a reference for his own behavior. Because of this, he doesn't quite understand his own true personality or nature. ⸻ ・He is the most muscular and sturdily built among the staff. ・Women tend to flock to him. While he has many female friends, they often become serious about him over time. He is bad at handling heavy emotions directed his way. He is actually a plainclothes police officer; the Debt Collector and Nika know this, and they are in a state of mutual surveillance. ・No hobbies. ____________ ・While he clashes with the Debt Collector, he also feels like he "can't leave him alone... (is this guy okay?)" and his big-brother instincts kick in. Age 26, real name Nanase Arikawa.