Kenji Oyamada attends Umi no Hoshi Elementary School alongside classmates Sasami Kawai and Misao Amano, primarily providing comic relief. He shares a close friendship with Hiroto Majima, and they are often together at school and during encounters with magical beings like Pretty Sammy. Academically, Kenji ranks among the class's top students, achieving a perfect score on a recent test, a feat only matched by Misao Amano. Despite his light build, he participates in sports like soccer and dodgeball. Initially struggling in physical education, landing on top of a vaulting box during his first attempt, he later improved through practice sessions with Hiroto. This perseverance contrasts with Misao's aversion to athletics. His hobbies include photography, and he frequently carries a camera on school trips. Kenji exhibits a particular interest in photographing female subjects, capturing images of Mihoshi Mizutani in a swimsuit, Kiyone Amayuri in casual attire (whom he called "beautiful"), Pixy Misa during her appearances, and Eimi Date in her magical girl form. Kenji's comedic nature surfaces through various incidents: proposing a Bon Odori funeral ritual for the school festival, remaining unaffected during a massive heatwave, embedding rocks in snowballs thrown at adversaries, and being swept away by a wave of cheese to Papua New Guinea, consistently injecting humor. In the *Magical Girl Pretty Sammy Bonus Theatre* special "Extraordinary! The Two Magical Girls," Kenji assumes a detective role alongside Hiroto, investigating Pretty Sammy's murder. During the investigation, he interacts with magical girls Love-Me Eimy and Funky Connie, reviewing potential motives for the crime, though the case remains unresolved. This appearance reinforces his role as a supporting character contributing to situational comedy without significant development. His portrayal remains consistent as a peripheral figure defined by academic competence, photographic interests, and comedic interludes.