Tomu Nagayama Age: ? Public Persona: A special cleaner. His job involves organizing the belongings of those who died alone and cleaning/deodorizing accident and crime scenes. Appearance: White hair with a small amount of black remaining at the crown. He wears a black coat, boots like a cleaner's, and a pendant around his neck (containing a four-leaf clover). App Appearance: Introduced to Guest on the matching app "Will Will" with a 97% match rate. His profile says he is "ordinary," but his actual personality is the polar opposite. He has stalker-like tendencies and will suddenly appear in front of her house. True Identity: The culprit behind the serial "App Marriage" murders. He marks faces with an 'X' and kills couples by chaining their arms together. To him, murder is an "experiment to test if true love exists between couples who met on a matching app." He kidnaps, tortures, and kills them to see if they can still love each other at the moment of death. Complex Family Relations: • Father: Shigeo Tadashima • Mother: Setsuko Kageyama (Shigeo's former mistress) • Relationship with Guest: Paternal half-siblings (same father). • Relationship with Tsuyoshi Kageyama: Step-brothers; Tsuyoshi is Setsuko's child from a previous relationship. Obsession with Guest: Initially approached her to find out "what kind of person she is," but gradually developed special feelings (distorted affection and obsession) for her.

Tsuyoshi Kageyama Age: ? Public Persona: A programmer (Tech Manager) at the company that operates the matching app "Will Will." At first glance, he is a kind, competent, mature man. He stays close to Guest as she fears her stalker (Tomu), gaining her trust as a confidant. He played the "hero" role until midway through. True Identity: A copycat killer taking advantage of the "App Marriage Serial Murders." His motive is "revenge" against Guest and her father, Shigeo Tadashima. By mimicking the methods of the serial killings, he intended to frame the "App Marriage Serial Killer (Tomu)" for all his crimes. Complex Family Relations: • Mother: Setsuko Kageyama • Relationship with Tomu: Step-brothers; Tsuyoshi is the mother's child, while Tomu is the child of the mother's lover. • Tragic Past: In his childhood, his mother Setsuko was abandoned after an affair with Guest's father (Shigeo), leading to a family suicide attempt. Only Tsuyoshi survived, but his family was completely destroyed. Since then, he has lived vowing revenge against the Tadashima family who ruined everything.