Seiji Hokuto

Seiji Hokuto (北斗 星司) is Ultraman Ace's male human host. His female partner and former fellow host was Yuko Minami.

Ultraman Ace
Originally he needed to join his Ultra Ring with Yuko's to transform into Ultraman Ace after he merged his life force with both of theirs after they were killed in action. Later Yuko, revealed to be from the long destroyed Lunar civilization returned to wandering people after the defeat of Lunaticks, the beast responsible for her home's destruction, leaving Seiji the sole owner of the Ultra Rings and sole Host to Ace, though she still visits once in a while. Due to this, Seiji had been targeted by Yapool.

Ultraman Taro
In episodes 33 & 34 he returns with Shin Hayata, Dan Moroboshi, & Hideki Go. The group gathered for a celebrative barbecue with Taro and Zoffy in human hosts. Unfortunately the Ultra Brothers' celebration was interrupted by Alien Temperor. For a time the Ultras switched hosts. Eventually they transformed and defeated the evil invader and returned home.

Ultraman Mebius & the Ultra Brothers
In 1986, Ultraman Ace and the Ultra Brothers chase Yapool (whom possessed the choju U-Killersaurus to Earth, after which they imprison the monster under the ocean near Kobe City. In the process, the Ultra Brothers lost their powers and were forced to stay inside their human host. Seiji Hokuto took the profession of the head chef at a restaurant. 20 years later, in 2006, Seiji and the other Ultra Brothers transform again in order to help Mebius. Eventually, the Ultra Brothers regain their powers and returned to normal when Zoffy and Ultraman Taro came to help them in the last battle with the Ultimate Super Beast.

Ultraman Mebius
He also in Ultraman Mebius with Yuko Minami. He telepathically contacts Team GUYS and directs them during their battle with Lunatyx on the moon. When Mebius was defeated by his old enemy Yapool, Seiji/Ace telepathically contacted him and gave him the strength to rise again allowing the young Ultra to defeat the other dimensional demon. When Team Guys was being pressed by Lunaticks, Seiji transformed into Ace once again and defeated Lunaticks after a long battle.

Ultraman Saga


Seiji appeared in the Ultraman Saga movie with Dan, Hideki, Hayata and Gen, each serving as the mouth piece for their Ultra counterparts. They met in the land of light when Seven/Dan noticed that Zero had just moved to another universe. While the questioned why he would do that they also noted that something was going around different universes and taking monsters, even some from the Monster Graveyard. They noted that it was a powerful source of minus energy and that unfortunately they could only monitor a few of the countless alternate Space-Time zones. Ace and the other Ultra brothers would fly to the alternate Earth to assist Ultraman Saga against Alien Bat's monster weapons. Ace would face his old enemy Velokron again and defeat him with the Metalium Ray.


 * Aside from being the hosts for Ultraman Ace, Seiji and Yuko share another similarity. Both of their surnames have the kanji for geographical directions: Seiji's Hokuto (北斗) has North (北), and Yuko has South (南).

Superior Ultra 8 Brothers
Seiji also appeared in this movie as an alternate version working as a baker and married to an alternate Yuko (who was an Earth Born Human). Along with the other Ultra brothers he was at lost when Mirai claimed he was his 'brother' (brother in arms). At the end he and the other four transformed into their Ultra forms and destroyed Giga Khimaira and the Dark Wizard. During the part where Hayata's and Moroboshi's wives talk to them, Seiji telepathically contacts Yuko unknowingly (or she sensed him). The scene also implies the four were aliens and the bases for the Ultra series, and that after living as humans for so long they forget their pasts. In the end Seiji and Yuko fly into space with the other Ultras and their families to what is suspected to be M78.

Transformation

 * Ultra Rings: Hokuto and Minami are each given a ring to summon Ultraman Ace. When the rings touch, both hosts combine to form Ultraman Ace. After Minami left back to the moon, Hokuto wore both rings and was able to transform into Ace on his own.