Kai Masaki is the son of Tsukiko Masaki, the younger brother of Kiriko Masaki and the best friend of Seina Yamada. He later marries Yoshiko Yamada and takes her family name, becoming Kai Yamada.
Background
Kai and Kiriko are also distant relatives to Tenchi Masaki. This led them and Seina becoming very close to Tenchi and his family.
Kai is an especially gifted tinkerer and he was the one who often fixed (or basically reconstructed) Seina's bicycle, "The Kai Special,"that would be wrecked as a result of Seina's bad luck. Just before Seina went into space, Kai announced that every single piece of the bicycle had been swapped out for another piece.
Kai rarely sees Dai Tennan (Kai's father) as Dai and Tsukiko no longer get along. Dai does apparently visit, sometimes secretly behind Tsukiko's back. Kiriko has never heard the full story of why the two don't get along anymore, as when Dai tries to tell her, Tsukkio cuts him off. It seems she must have liked him at some point and he must have been sympathetic to her when she was suffering from the loss of Kiriko's father but it seems he suffered some extreme personality change around the time of Kai's birth and basically started acting more like a typical Tennan.
At the end of the GXP anime series, when Seina is about the get married to the four girls, Kai and Yoshiko Yamada (Seina Yamada's sister) act very much in love and seem to be heading towards marriage themselves.The GXP novels characterize it more as the two of them simply going out.
Kai appears briefly in Tenchi Muyo! Ryo-Ohki OVA 4, heading off for a trip with school friends (in a section that takes place before Seina's ill-fated wedding). Tsukiko catches him packing condoms. He also takes a little extra time to hug Mizune Masaki ("Mizune-oneechan") in order to feel her breasts, which she happily smothers him with. "Please don't make our idiot here any more idiotic," is Tsukiko's reaction to her encouraging his bad behavior.
In the OVA 5 episode, I am sure you have your opinion on the matter, but please consider the matter closed, it is incidentally confirmed (but not directly) that Kai has married Yoshiko by the time of the episode (set approximately 10 years after the end of the GXP anime conclusion). He is seen passing by in a Yamada truck with his father-in-law, Nishia. As they pass, Tenchi (while talking about his upcoming marriage announcement) refers to both Seina and Kai as "sempai" in the subject of marriage. Yoshiko and Kyoko cameo as part of the huge group cooking food at the Masaki home.
Kai showing Seina the development of the family store
Most in Masaki Village seemed to assume that once Kai knew about his alien heritage, he would go into space, like most of them do, and maybe reconnect with his father. Instead, in Tenchi Muyo! GXP Paradise Starting, which takes place before the core events of OVA 5, Kai confirms to Seina that he is engaged to Yoshiko and reveals that when he got his blessing to marry her, he, Nishia, and Kyoko made an agreement to "swap sons" with Tsukiko. Kai would take the Yamada surname and live with the family while he would help and become heir to the burgeoning Yamada Super Shopping Center. Seina would henceforth call Kai's former home (Tsukikio's house in Misaki Village) his home. True to his father's Tennan bloodline, Kai is actually a very eager participant in helping the Yamada family business expand and thrive and shows no interest in going into space.
Voice credits
- JAPANESE - Hisayoshi Suganuma (菅沼 久義)
- ENGLISH - Brad MacDonald
Etymology
- Kai's surname Masaki means "straight grain, spindle tree, (kokuji)" (柾) (masa) and "tree, wood" (木) (ki).
- It's only mentioned briefly in a GXP novel, but Kai's father is a member of the Tennan family. Meaning Kai is also a relative of Seiryo Tennan.
