Ultraman: What do you mean by saying L77 is about to explode?

Reincarnated as the younger brother of Leo and Astra, Prince Koul of Nebula L77 has always dreamed of transforming into a towering giant of light, 50 meters tall, and becoming a revered cosmic police officer. However, during his coming-of-age ceremony, a shocking reality sets in: while his brothers successfully transform into giants of light, Koul remains stuck at a mere 1.8 meters. Not only is he unable to achieve giant size, but as a pure-blooded Ultraman, he has unexpectedly awakened the rare Reionics bloodline. To make matters more intriguing, an albino juvenile Zetton, which he has named "Zetton," now stands by his side. With his home planet L77 and the neighboring planet D60 both on the brink of destruction, Koul readies himself for action, armed with the Battle Device in his left hand and the Cosmic Beast Fist in his right. As he gazes at Zetton, who is also mastering cosmic fist techniques, a determined smile spreads across his face. Driven by his unwavering resolve to save L77 and D60, Koul embarks on an extraordinary journey, one that will test his courage, his abilities, and the unbreakable bond he shares with his loyal companion, Zetton.