"Do not give up until the end!"
- ―Tsutomu encouraged Hiroshi and his friends after feeling remorse for unleashing King of Mons.
Tsutomu Shinsei (新星勉 Shinsei Tsutomu) was the primary protagonist in the movie Ultraman Tiga, Ultraman Dyna, & Ultraman Gaia: The Decisive Battle in Hyperspace.
Ultraman Tiga, Ultraman Dyna, & Ultraman Gaia: The Decisive Battle in Hyperspace
An average boy, Tsutomu always had a problem with coping with the society due to lack of confidence. He also not good in exercises and studies, often found solace in watching Ultraman series even having collections of toys at his room.
One night, while watching Ultraman Gaia, her mother scolded him for his poor achievements in his recent test. Later, while she was sleeping, Tsutomu sneak out and watched the episode again. Later, the television transformed into a portal and teleported him into hyperspace where he sees a mysterious girl and behind her a scene of mass destruction at his hometown.
The next day, a new student named Lisa Nanase moved to Tsutomu's school. With both of them isolated from students (for Tsutomu, even his best friend Yu left him due to his Ultraman addict), Lisa decided to show him something. The next day, after school, she presented him and Yu the Red Sphere, capable of granting wishes. Witnessing his Ultraman Gaia drawing on the floor, this gave him an idea and wished Gamu Takayama to appear in his world. Hiroshi Kashimada, a bully sees this and confiscate the ball from him. He summoned Satanbizor via the ball and the alien rampaged with Tsutomu regain the ball. Gamu quickly transform into Ultraman Gaia and finished the alien with ease, despite having his Color Timer blinked in the beginning of the battle. Gamu was later brought to Tsutomu's hideout in order to cover himself from crazed fans. He revealed to Gamu that in his world, Ultraman Gaia is a television series and that it was him who brought Gamu in the first place. Tsutomu gave Gamu his favorite book, Gulliver's Travels which he accepted as he scanned the Red Sphere and the authorities surround him. Before the police forces could arrest him, Gamu forcefully teleported to Aerial Base.
Meanwhile, Hiroshi and his friends capture Tsutomu and Yu while regaining the Red Sphere in their possession causing it turned larger and grow spikes, even corrupting them. Hiroshi dragged Tsutomu and Yu to their school's rooftop and summoned his creation, King of Mons into reality. Lisa appeared, having watched the full event. However, Gamu appeared in the nick of time fighting the monster with his XIG Adventure and later as Gaia. However, the Ultra appeared having difficulty in battling the monster, Tsutomu removed the ball from Hiroshi, causing him and his subordinates to regain their sanity as they felt remorse of their actions. However, it landed on Yu's hands, corrupting him as he shouted his desire to destroy the world, spawning Bajiris and Scylla. As King of Mons' Cremate Beam hit the school, the ball moved from Yu's possession, regaining back his conciousness. Tsutomu quickly grabbed the ball and summoned Ultraman Tiga and Ultraman Dyna. After the Ultras finished battling the monster, the ball returned back to its original form. Lisa revealed herself to be an interface of the Red Sphere. She urged Tsutomu to wish the ball to disappear, as he forcibly agreed, causing it to vanish, followed by Lisa, Tiga, Dyna and Gamu but not revealing that he can still meet him due to his book, returning it to Tsutomu's hands.
The same day later repeated by the Red Sphere but the real Lisa Nanase appeared as a new student. Tsutomu later brought her the school's rooftop to show her his book, Gulliver's Travels with Gamu's signature and his words "This world will not perish as long as we believed in the future" at the last page. An XIG Fighter EX belonged to Gamu appeared at the sky, passed the two students and vanished. Unfortunately, Lisa missed the opportunity to witnessed the jet.
Tiga, Dyna, and Ultraman Gaia novel: The Adventure in Hyperspace
- Tsutomu is the first main character in the Ultra Series not to be an Ultra host.
- He also the first main character to be a child.