yamamoto naoki

First appearance: Battle 63
Age: 12
Type: Sei
Type: Katsujin Ken
Martial Arts: Jujutsu (Yamamoto Style)
Yamamoto Naoki is the son and disciple of Yamamoto Taiki. He assisted in Kenichi's training to counteract dirty tactics.
Naoki employs a distinct style of Jujutsu but also integrates strategies into his combat, defeating Kenichi in their initial match. He and Kenichi ventured into the Cave of Death, which serves either as punishment or training. He claimed that his father had defeated a Tengu and sealed it inside the cave, though it was actually his father in disguise. He stated that if he could hit the Tengu, he could visit the city, which was his dream. In a subsequent match, he lost because Kenichi had trained himself to counter Naoki's techniques. After losing, he and Kenichi became friends, promising to fight again someday.
In an additional scene, he encountered a kappa but mistook it for a city boy. Occasionally, he appears in flashbacks mentioned as Kenichi's opponent or as an example of various methods to train children or disciples in martial arts.
Naoki was also enrolled in the middle school Honoka attends as a first-year student. There, he found his desk vandalized and himself bullied, but he mistook it for the school's norm and continued living normally. Upon realizing it was bullying, Naoki was tempted to retaliate but decided not to use his martial arts improperly. When he witnessed those bullies being harassed by high school students, Naoki saved them with his Jujutsu, earning their gratitude and indirectly convincing them to stop bullying him. Although he found it strange that his desk was clean the next day, believing something was out of the ordinary.