- Gender: Male
- Age: 16
- Hair: Black
- Eyes: Grey
- Nationality: Japanese
- From the manga Ranma 1/2, by Rumiko Takahashi
- First Appearance: Chapter 9
The eldest son of a wealthy family, Sentarou has been trained since childhood in the Japanese tea ceremony, and specifically in the martial applications of this ancient and respected cultural art form. This involves the combatants remaining in a proper sitting posture at all times, as well as the use of tea ceremony implements such as pots, ladles, teaspoons, the stirring brush, and so forth as weapons. As well, Sentarou is known to brew paralysis and knockout drugs which he slips into his opponent’s tea.
Sentarou lives with his grandmother, who presumably trained him in Martial Arts Tea Ceremony. As the heir to their school, he is intended to be married to Satsuki, the heir to another school of that art, and a former Miss Tea Ceremony of Japan. However, Sentarou was quite opposed to this marriage and was seeking a new bride who could defeat Satsuki, due to the fact that when he met his bride-to-be, he found out she was, apparently, a monkey.
Despite his courtly manners and ostentatiously humble demeanour, Sentarou is a rather sneaky, conniving, and unpleasant person who will do just about anything to get out of marrying his simian fiancee, including quite possibly murder. Also, his meek appearence belies his true skill in Martial Arts Tea Ceremony, whose ridiculous appearence belies its true combat effectiveness. Sentarou is quite qualified to both fight in and teach others the style; as well, his strength and stamina are quite superhuman. He is capable of taking on someone of Ranma’s caliber in a tea ceremony match for at least 12 hours without losing or collapsing from exhaustion.