Teooi Arima is the main protagonist of the series. He was the son of a happy family whose father was a noodle shop owner. Coming back from school one day he learns both his parents were killed in an automobile accident, which he does not believe to be the truth.
His grandfather Isshin Arima is the owner of the Arima Financial Combine, a very wealthy and powerful industry in Japan and offers to take Teppi in after the deaths of his parents. Teppi agrees in the hope that through his grandfather's influence he can find the details of who murdered his parents and seek revenge. Isshin then announced, much to Teppei's surprise, that he is to become the successor to the Arima corporation. He is enrolled in the most prestigious private school in Japan.
Teppi is a good swordsman and prefers sword-drawing techniques. He is also engaged to Sylvia before even meeting her, they bond significantly through their swordplay. They are the only two at the school who pose a challenge to one another in that skill.
Several women are interested in him and taking his maid Yu Fujikura's advice he does not immediately reject their affections instead treating them as 'opportunities'.