Riki Nendo, a student at PK Academy, boasts a muscular frame, a sharp Mohawk with yellow bangs against black hair, a cleft chin, and a scar over his left eye. His family mirrors his distinct features: his late father sported a scar over the right eye, while his mother, Midori, carries scars over both. The household also includes a pet named Koriki No. 2. Initially a bully who replicated Saiki Kusuo’s notes, Nendo’s demeanor changed after crediting Saiki with saving him from a false accusation by classmate Takahashi. This misconception spurred him to shadow Saiki as a self-appointed protector, insisting on rituals like post-school ramen outings. His unwavering presence and social obliviousness fuel comedic exchanges, yet he occasionally pierces through lies with startling perceptiveness, spotting flaws in fabricated tales. Saiki cannot read Nendo’s mind due to the seamless sync between his speech and simplistic thoughts, a quirk stemming from his lack of mental complexity. Despite this, Nendo exhibits fierce loyalty, often menacing those who approach Saiki. Though academically disinterested, he once aspired to carpentry—a contrast to his mother’s mistaken belief in his genius when he rushed through schoolwork. The kanji 力 (“power”) in his name aligns phonetically with *nendōryoku* (psychokinesis), tying into the series’ psychic wordplay. A guardian spirit dubbed an “old hag” lingers near him, as observed by psychic medium Toritsuka Reita. Nendo’s role remains steady as Saiki’s loyal, simple-minded ally, underscoring themes of accidental friendship and the gap between tough exteriors and genuine intent. His presence anchors the chaos of Saiki’s social world, blending comedy with unexpected depth through steadfast camaraderie.