[O”kahbeh Rintah(rO) {Japanese “ro”}/ “O”kahrEn/ HOEn KeyOmah]

Voice: medium-medium low

Personality: Rintarou is a melodramatic, eccentric and rarely tsundere individual. He is a self-proclaimed mad scientist, who likes to assume the nickname "Kyouma Hououin", and often uses this to introduce himself to others. For the most part, people do not seem to care and instead address him by his actual name or by 'Okarin' (his nickname), much to his chagrin.

He usually gives off the impression of being delusional and paranoid, engaging in strange mannerisms such as talking to himself on the phone and engaging in fits of maniacal laughter often; he had a severe case of Chuunibyou as seen at the start of the series. This is in fact a façade he wears in order to make life interesting for his dear childhood friend Mayuri. Initially, he is portrayed as being rather arrogant, however, it is later suggested that this is due to Rintarou's eccentricities and social awkwardness. As the story progresses he becomes more serious. Regardless of what one may think, he is actually a very kind and caring individual which is shown by the actions that show his true colors.

Background: He and Itaru are both students of Tokyo Electronics University, and have been friends for roughly three years, according to his words, although Itaru claims that their friendship was only about a year old. Rintarou founded the “Future Gadget Laboratory", a small research institution situated above a CRT store. It is an area where he and his fellow Lab Members create "Future Gadgets for the betterment of mankind". He is Lab Member 001. Rintarou has always been close friends with the second Lab Member and co-founder of the "Future Gadget Lab", his childhood friend Mayuri, who he made a vow to protect when they were young. Rintarou lives an average life with his small group of friends until he creates the Phone Microwave with Itaru.