Riko Kitsuchi, formally named 橘地莉子 (Kitsuchi Riko), is a disciplined and meticulous classmate of Hime Gotō, actively participating in the Meguro River Detective Agency alongside close friends. As chairperson of her class’s disciplinary committee, she diligently oversees student conduct, frequently intervening to address thoughtless remarks from peers like Hina Toumi toward Hime.

Her appearance includes waist-length hair parted centrally, often adorned with a pale-hued headband, and she was initially depicted wearing glasses in the manga’s first chapter. Both her surname and character design intentionally parallel Chiri Kitsu from the author’s prior work *Sayonara, Zetsubou-Sensei*, reflecting shared visual and nominal motifs.

Within the detective agency, introduced in chapter 11, she engages in collaborative investigations driven by curiosity and camaraderie. A defining trait is her steadfast belief in Santa Claus, blending mature responsibility with earnest, childlike sincerity. Her established narrative focuses on these traits and affiliations without elaboration on personal history or extended development.