Mitsuru Fujiwara is a frequently absent high school student, the son of a Shinto priest with whom he shares a strained relationship. His past involves a relationship with an older woman, Yujima Hijiri; her subsequent suicide left him haunted by her ghost. This traumatic experience fuels his complex attitudes toward domination and romantic attachment.

He exhibits persistent stalking behavior toward Saiki Misaki, pursuing her, photographing her covertly, and bombarding her with text messages despite her changing contact information to evade him. Misaki rebuffs him as a pest. His stalking escalates to intrusive acts like possessing and distributing unauthorized bathroom recordings of her. Interpretations of his actions range from tragic expressions of loneliness to self-centered violations of privacy.

Despite this problematic conduct, Mitsuru demonstrates protective instincts, occasionally aiding Misaki in her cases. He notably intervened during an assault on his classmate, Ai Kunugi, tracking her attacker and providing critical information that resolved the situation. He also participates in investigations alongside the Livelihood Preservation Group, collaborating with Misaki's partner, Souichirou Kadotake, despite their contrasting personalities.

His connection to Ai Kunugi extends beyond that incident through their shared class affiliation. He displays moments of concern for others, including saving lives during supernatural investigations, though his motivations remain tied to his fixation on Misaki. His character lacks significant development or expanded backstory beyond the original manga and OVA adaptation.

The ghost of Yujima Hijiri remains an ongoing source of emotional conflict. This unresolved trauma shapes his interactions and contributes to his portrayal as a potentially tragic figure grappling with loss and maladjusted coping mechanisms. His role involves confronting supernatural threats linked to Japanese suicide culture, though his personal arc remains secondary to the protagonist's story.