OVA
Description
Kenichi Saruyama is a 15-year-old first-year student at Sainan High School who turns 16 in his second year, born on April 15, making his zodiac sign Aries. He stands 166 cm tall, weighs 66 kg, and has black eyes and spiky black hair, with blood type B. Kenichi is the best friend of Rito Yuuki, having known him since their junior high days.

His personality is pronouncedly perverted; he frequently attempts to peek into girls' hot springs or locker rooms, often involving Rito in these plans and deflecting blame onto him when caught. He maintains a collection of bikini model posters and magazines in his room. Despite this behavior, he is a loyal friend who understands Rito's shyness and clumsiness around girls. He is aware of Rito's feelings for Haruna Sairenji and occasionally offers advice or tries to create opportunities for Rito to confess. However, he feels significant jealousy toward Rito due to Rito's proximity to attractive girls like Lala Satalin Deviluke and Haruna.

A notable aspect of his history is his sincere romantic interest in Yūsaki Riko, unaware that Riko is actually Rito transformed into a female by one of Lala's inventions. He often imagines romantic or ecchi scenarios involving her, causing Rito discomfort. His friends know the truth but have not revealed it to him.

Throughout the series, Kenichi is a frequent companion to Rito, joining him on trips to beaches or pools with other main cast members. He provides comic relief as a luckless individual whose schemes consistently fail or backfire. In the sequel series, his appearances become less frequent, though he continues to express jealousy toward Rito and occasionally partners with the equally perverted Principal in their pursuits, which continue to end poorly. His crush on Riko remains unchanged.

His relationships center on a small group. He considers Rito his best friend despite envying Rito's circumstances. He is not particularly close to Lala but finds her physically attractive due to her large breasts and refers to her with the "-chan" honorific; Lala has assisted him, such as helping arrange a date with Riko. His relationship with Haruna is minimal; she dislikes his perverted comments, though they remain acquaintances through Rito.

One unusual event involved an unnamed cat-like alien woman who developed feelings for him and saw him as a suitable father for her child, though this was isolated. According to series lore, no other characters have expressed romantic interest in him.

The etymology of his name reflects his character: "Saruyama" combines the Japanese words for monkey and mountain, referencing his perverted nature, while "Kenichi" means healthy and strong, and one.