Ultraman: As the Original Galaxy, I Save the Multiverse

(Before reading the main story, please be sure to read the synopsis first. The timeline, plot, and some character relationships have been changed. Please don't read if that bothers you.)

[Power fantasy + no female lead + the spirit of Ultraman + Galaxy + New Generation + debut author]

In a world without Ultra Warriors, people live in the shadow of monsters.

Lin Guang scrapes by here with his younger brother, Lin Xiang.

When they once again face a life-or-death crisis against Red King, Lin Guang earns Galaxy's approval and transforms into Ultraman Galaxy to save the world. Along the way, his younger brother Lin Xiang also earns Ultraman Victory's approval, transforms into Victory, and fights alongside him.

After resolving the crisis in this world, the brothers transmigrate through a cosmic gateway to the Land of Light. They then travel through the universes of various Ultramen, offering help, and eventually face Lugiel and shatter his scheme.

“Trainer Taro, who's that Ultra Warrior standing atop the Plasma Spark Tower?”

“That's...” Taro gazes at the figure and sighs. “He's a hero to our Ultra race and to every universe!”

(The pacing is a little slow early on and may pick up later, though even I, the author, can't say for sure.)