Sentaro Daimonji

Sentaro Daimonji is the heir to the Daimonji School of the Martial Arts Tea Ceremony, of which his grandmother is the current head.

Sentaro means "boiling great son," which may be a reference to the fact that he is about to inherit his family's legacy. Daimonji is "(Dai) faithful service to those older + (mon) problem (or some monkey reference) + (ji) pity".

Overview
The heir to the House of Daimonji and fiancé of Satsuki Mikaoji, Sentaro is a user of the martial arts style of tea ceremony. As sole heir to the school, he is expected to marry, but wishes to choose his bride rather than have one selected for him.

Martial Arts Tea Ceremony
After finally met his fiancé, Satsuki Miyakoji, Sentaro can't bring himself to like her and ends up fleeing his home on his horse. Whilst riding, he loses consciousness, but is stopped single-handedly by Ranma, who'd been trying to escape from Shampoo earlier. When Sentaro comes to he is met by Ranma (who's in his female form due to a downpour earlier) and offers her some tea. Ranma accepts the offering, but soon regrets it as Sentaro laced it with paralysis potion and puts her on the back of his horse before riding off with her back home.

As he heads home, Sentaro passes Akane, who notices Ranma on the back of Sentaro's horse and tries to stop him. However, Sentaro fends off Akane's attack and pins the hood of her coat to a nearby lamppost with a Tea Ceremony spoon. Some time after returning, Sentaro has Ranma dressed into a wedding Kimono.

Once Ranma awakens, Sentaro tries to explain himself, but Ranma doesn't want to her any of it and attempts to leave. Fortunately for Sentaro, his Grandmother ends up making Ranma accept to participate in a match of Martial Arts Tea Ceremony to see if she's worthy of being Sentaro's bride. Sentaro then quickly plans on starting Ranma's training the next morning, but is horrified to learn of Ranma's Jusenkyo curse. As Sentaro weeps at his misfortune, Ranma suggests he just gives up and agrees to marry this "Miss Satsuki" he's engaged to, but Sentaro refuses to give up.

Just then Akane arrives to retrieve Ranma, but ends up being wrapped up in by Sentaro as well as a possible replacement for Ranma. Unfortunately, despite being taught by Kasumi how to perform Tea Ceremony, Akane lacks the patience to do so, making Sentaro decide to go back to having Ranma fight in the match. Sentaro begins is training of Ranma, who initially struggles to match Sentaro's ability to glide seamlessly across the floor. Luckily, after Ranma observes how Sentaro's Grandmother is able to walk on the ceiling she soon becomes a master of Martial Arts Tea Ceremony like Sentaro.

After a long night of practice, Sentaro takes Akane and Ranma to where the fight against Miss Satsuki will take place. As Sentaro describes Miss Satsuki to the pair, she initially seems like the perfect wife, until Sentaro show them Miss Satsuki in person, who turns out to be a monkey! Now knowing that Miss Satsuki is a monkey, Ranma immediately goes against the idea of fight, taking pleading from Sentaro along with an unprovoked attack from Miss Satsuki before she ends up participating.

Sentaro doesn't watch the fight for long, however, as he takes Akane outside with him and declares that he will mortally wound Ranma and Miss Satsuki so that he can become engaged to her instead. Once the fight overflows to outside of the arena, Sentaro waits until Ranma's about to defeat Miss Satsuki to interrupt the fight and attempt to enact his plan. However, just before he is about to stab the paralysed Ranma, Akane kicks him across his estate. As he flies, Sentaro ends up crashing into the real Miss Satsuki, who'd sent her monkey, Sanae, in her place as she was too shy to initially go herself.

Having finally met the real Miss Satsuki, Sentaro instantly falls in love with her and the pair are soon married and off on their honeymoon. Sentaro also makes sure to send Ranma a latter along with a picture of him with Miss Satsuki. Despite the letter saying they'd probably never meet again, as Ranma reads the letter, Sentaro and Satsuki appear at the Tendo Dojo as they'd gotten lost whilst riding Sentaro's horse...

Non-canon Appearances
Sentaro is mentioned in the alternative version of Lambada Ranma, which features characters from later in the anime's run. He also has his own song in the Fighting Songs Karuta album, Hanashi wo Kiite Okureyasu.