Riki Nendō stands 191.3 cm (6'2") with a muscular build and a distinctive mohawk featuring black hair tipped in yellow. A prominent scar over his left eye sets him apart from his family; his late father had a scar over his right eye, while his mother, Midori, has scars over both. He typically wears his PK Academy uniform open, revealing casual t-shirts underneath. Initially a freshman bully demanding copied notes from classmates like Kusuo Saiki, Nendō's path changed after being falsely accused of theft. Believing Saiki cleared his name, he developed intense loyalty, declaring Saiki his closest friend. This led to daily invitations for ramen and protective actions, intimidating perceived threats to Saiki. Their dynamic evolved into a trio with classmate Shun Kaidō, with peers viewing Saiki as the group's leader. Nendō exhibits extreme intellectual simplicity, often needing repeated explanations, though he occasionally solves problems unexpectedly during Kaidō's delusional scenarios. His thought processes are notably slow, rendering him immune to telepathy. Despite his intimidating look, he shows consistent kindness and protectiveness, especially toward the vulnerable. He rescued a girl who rejected him from drowning and accepted her apology, and patiently cares for his pet hamster, Kojikara No. 2. He fears water and lacks any sense of direction. His childhood dream was to become a carpenter. His family includes his mother, Midori; his deceased father, Takeuchi Riki; and his stepfather, Nakanishi Kouta. They share similar facial features and naming conventions tied to psychic terminology: "Nendō" relates phonetically to "nendōryoku" (telekinesis), while "Riki" (力) means "power."