Nobuyuki Masaki (柾木 信幸, Masaki Nobuyuki) is the father of metaseries protagonist Tenchi Masaki, and works in the city as an architect. Although he has shown that he is less responsible than his son, Nobuyuki does care deeply for Tenchi, and after losing his wife, Nobuyuki worked hard to raise him. He is also a voyeurist/peeping Tom and tries to encourage Tenchi to be more sexually active and not as shy towards women (only for his efforts to have the opposite effect). Nobuyuki has appeared in all Tenchi series'. In every series, Nobuyuki designed and built the house that Tenchi and his extended family live in.
Nobuyuki is a direct descendant of Yosho Masaki Jurai, the Prince of planet Jurai, offspring from his marriage with his first wife Kasumi (he has addressed Yosho/Katsuhito both as "father" and as "grandfather", but the exact nature of the relation, how many generations separate them, has yet to be varified). In the Light Novels, Tennyo reveals that Nobuyuki is one of the few Masaki family members to remain on Earth, and not join the GP or other branches of the Academy. She also gives an age for Nobuyuki of roughly 120.
Due to his (diluted) Juraian heritage and body enhancement from the Galaxy Police Academy, Nobuyuki has lived much longer than any normal Earthling. Nobuyuki met Katsuhito's daughter Kiyone Masaki when Nobuyuki was a young boy. Kiyone seemed to love teasing him, much to the despair of those around them. She nicknamed him "Nobu". Eventually, the two fell in love, and married, which the Masaki Village wasn't too keen on, apparently. In time, they bore two children, Tennyo and the main protagonist Tenchi. However, Kiyone died when Tenchi was still a young boy and Tennyo left Earth shortly after. He tends to conceal the fact he looks like he's still in his 20s, appearing to be in his mid to late 40s. Though he allowed his true appearance to show during his wedding to his second wife, Rea.
Originally, he and Tenchi lived in the city, where he would work and Tenchi would go to school. But after the space pirate, Ryoko, was awakened, Nobuyuki saw Tenchi with her and was surprised that Tenchi had a girl in his room. Nobuyuki attempted to videotape their 'private session', but the Juraian Princess, Ayeka, arrived in her ship, and Nobuyuki was captured along with the house by Ryoko while escaping from Ayeka.
Afterwards, the house was permanently relocated next to the Masaki family shrine, and Nobuyuki soon moved back into the city, living in an apartment with his assistant, Rea. He and Rea became engaged and married.
Before the ceremony, Tenchi was initially angry when he found out that the story he was told about how his late mother, Kiyone, died was fictitious. Eventually, Tenchi and Nobuyuki talked and Tenchi apologized for his earlier behavior and reveals that he's long-since accepted his father's new wife, as she had long been more of a mother figure to him after his birth mother, Kiyone, had died, and having her around wouldn't be any different. Nobuyuki admitted that it was because of that fictitious story that they hesitated to tell him about the truth behind Kiyone's death or that Kiyone was also a prankster.
In the Tenchi Universe continuity, Nobuyuki is Katsuhito's son-in-law, though he prefers to address Katsuhito as father though Nobuyuki married into the Masaki family. Nobuyuki's personality is very similar to that of the OVA series. One difference is that since Nobuyuki and Tenchi have always lived with Katsuhito, Nobuyuki constantly complains about the long commute and how he can't catch a break from work with so many development projects. Nobuyuki has also a few times hit on his female secretary and even brought in a bouquet of flowers for her. Although Nobuyuki had to travel with everyone to Planet Jurai and found out the truth about the mysteries revolving around his son and father-in-law, by the time he had gotten back to Earth, Nobuyuki had not changed at all.Achika (the name of Tenchi's mother in Tenchi Universe and Tenchi in Tokyo) were in high school, Nobuyuki was very shy and was not the sleazy pervert back then. Nobuyuki used to draw houses as he had a talent for drawing before he got into his job as an architect and also loved to record him and Achika on a video camera, although both of them were too shy to express their feelings towards one another. Although Nobuyuki was trapped with Achika along with Kain in a second dimension, it was watching Nobuyuki getting knocked unconscious by Kain that awakened Achika's dormant Jurai powers. Both were rescued by Tenchi, Ryoko, and Ayeka and then both of their memories were erased so it wouldn't affect the future. Ironically, the dream house that Nobuyuki had drawn for him and Achika is in fact the house that he, Tenchi, and their extended family now live in.
In the movie Tenchi Forever!, Nobuyuki only makes a brief cameo at the beginning of the film. After six months since Tenchi had disappeared, Nobuyuki told Katsuhito that after he filed a missing-person report to the police for Tenchi, they had found nothing. Nobuyuki became worried about Tenchi, but Katsuhito reminds Nobuyuki that Tenchi is not a weak man.
Nobuyuki was also married to Achika in this version.
Magical Project S
Nobuyuki makes a cameo appearance as the character Nobuyuki Onijigoku (aka Oni Jigoku in the Pioneer subtitles) in Episode 10 of the Pretty Sammy television series. Onijigoku is the rival of the Hagakure clan and has attempted to force the head of the Hagakure clan, Genjuro Hagakure out of his ninja theme park so he could convert it into a wild-western style theme park. Despite temporarily having the help of both Genjuro's grandson Binpachi, as well as Pixy Misa, Onijigoku wasn't able to achieve his plan. However Genjuro convinced him that the theme park can be a ninja/wild-west theme park, but still had Onijigoku and his assistant bound to his theme park entrance as punishment for what he had tried to do.