Moto Azabu High School student
Asanuma is a high school who looks up to Mamoru Chiba. In the Materials Collection, it is noted that Asanuma has a home in Sendaikazue and is the only child of his family.
Asanuma has blond hair and blue eyes. He is often seen wearing a school uniform. Also, he occasionally wears glasses.
Asanuma appears first in Act 15. He is a student at the prestigious Moto Azabu school. The school is a combination of Junior High school and High School. Asanuma is a first year student in Junior High, while Mamoru is in High School at the beginning of the manga. He is very curious and has a special interest in the supernatural. He belongs to the Science Fiction club at his school, and reports and collects information on UFOs and other supernatural things. He often takes notes or pictures of anything unnatural that he sees.
Asanuma greatly admires Mamoru Chiba, and wants to be like him, often following him around. He once secretly sees Mamoru heal himself of a scratch, but decides not to mention the incident to anyone. He has also overheard Luna talking to Usagi. He begins to hypothesize the members of the group of friends are not human. One day, Makoto isn't feeling well, so he walks her home. He touches her arm, and static shocks him. She begins saying that she can manipulate thunder and lightning, but quickly stops herself and pretends to be delirious.
Curious, Asanuma questions Makoto about the strange events that occur around the group, but she denies everything. Eventually, when he reveals that he has heard Luna talking to Usagi, she reveals to him that she is Sailor Jupiter. She also tells him the identities of the other Senshi. He is amazed by this, and tells her that he has deep respect for their mission. He tells her that if he had the power, he would work to protect her.
Asanuma also appears briefly in the Infinity arc helping Mamoru with Chibiusa and her friends when they attend the amusement park next to the Infinity Academy.
He also appeared in the Stars arc briefly, where Usagi asks him if he knows Mamoru's phone number or apartment number in America. She replies that she doesn't, but offers to ask Mamoru's friends.
- In his concept art, it is noted that his mother drives a red Porsche.
- It is also noted that he keeps a red notebook that he uses to take notes on everything, including Mamoru's actions. He often keeps this notebook, as well as a pen, in the breast pocket on the shirt of his school uniform.