Tatewaki Kuno, age 17, is the self proclaimed "rising star of the high school fencing world," and has given himself the nickname "Blue Thunder". Upperclassman Kuno, as he prefers to be called, is a well-spoken ladies man. He often quotes Shakespeare or Japanese poems and haiku.

Before Ranma arrived, he was devoted to Akane Tendo, even going so far as to announce to the entire student body that if any of them could beat Akane in combat that they would be allowed to date her. Kuno often said that if Akane could beat him, he'd allow her to go out with him.

Kuno hated Ranma from the moment they met, and couldn't believe he could be engaged to Akane. Later he met Ranma in his female form and instantly fell in love. "The Pigtailed Girl", as he calls female Ranma, and Akane became his reason for living and he has dedicated himself to making the difficult decision of somehow choosing between the two.

Kuno and his sister are some of the few that actually don't understand that male and female Ranma are the same person. Kuno's hatred for Ranma also stems from the fact that he believes he has somehow romanced the innocent Pigtailed Girl away from him.