Natsuhiko came to Ula ula Island to find Kapu-Muu mainly because he wanted to learn from it the origin of the black Crystal Stone.
He had already taken this black Crystal Stone very seriously, even thinking it was a part of Necrozma's body.
Yet he hadn't expected Kapu-Muu to still give him a "surprise."
The black Crystal Stone turned out to be Cosmog's true sleeping form.
With Kapu-Muu's Help.
Cosmog regained its original appearance.
Although it was still asleep, and no one knew when exactly it would awaken.
At least the worry in Natsuhiko's heart was greatly eased.
The unknown is always what makes people most anxious.
Natsuhiko, knowing Cosmog's origins, had absolutely no intention of generously handing Cosmog over to the Alliance for research.
Even though.
By studying Cosmog, it was very likely the Alliance and the Ethereum Foundation could make huge progress in their research on Ultimate Beasts, Ultimate Space, and even Ultimate Aura.
But Natsuhiko still wasn't planning to let anyone know.
An existence like the Golden Lion.
Obviously it's better kept for himself to ride.
Besides asking about the black Crystal Stone, Natsuhiko had another goal: to have Kapu-Muu Help him carry out special training.
Of the four Island Gods, only Kapu-Muu has this kind of "hobby."
And.
Kapu-Muu's special training is quite interesting.
It doesn't teach any battling styles or methods.
Nor does it teach any specific Techniques.
It teaches Pokémon how to better control their own energy.
How to understand themselves better, to have a clear sense of their own positioning.
It's precisely thanks to its Help that in the original story Ash Ketchum's Lycanroc—who used to go berserk at the drop of a hat—was ultimately able to control its own will and emotions.
And whether it's energy usage or understanding one's own ability and will, all of it gave Natsuhiko's Pokémon no small amount of Help.
Especially regarding energy.
Once Natsuhiko learned that the main gap between Elite Candidate Level Pokémon and Elite Trainer Level Pokémon lies in the level of energy, he had already made some adjustments.
But knowledge in this area was still far too scarce.
Even though Natsuhiko had consulted quite a few Elite Trainer Level powerhouses—among them not a few members of the Elite Four and even existences like Giovanni—there were still more or less some lingering doubts.
Kapu-Muu's existence neatly made up for that.
What it taught.
Was not only Natsuhiko's Pokémon, but Natsuhiko himself.
And going to Kapu-Muu for special training had another benefit.
Namely that there was absolutely no need to worry about the Pokémon's condition.
Even if they were exhausted or injured, Kapu-Muu's abilities could Help the Pokémon recover very well.
It was training with zero worries about repercussions.
And after learning that Kapu-Muu actually possessed this kind of ability.
Natsuhiko's Pokémon completely "went crazy."
Especially Beedrill, Alakazam, and Infernape.
They're all training maniacs by nature, the kind that once they start training, they just can't stop.
Usually it took Natsuhiko ordering them not to overtrain for these Pokémon to reluctantly suppress the restlessness in their hearts.
But now.
With that concern gone.
The Pokémon completely "lost control."
Their training became utterly unrestrained.
They had a fairly decent "teacher" to instruct them and answer questions for free.
And could also Help restore their condition unconditionally, without worrying about hidden injuries.
Could anything possibly make them happier than this?
Nope!
Moreover, under the lead of the three training fanatics—Beedrill, Alakazam, and Infernape—the motivation of Natsuhiko's other Pokémon was also more or less pulled up.
Even the usually laid-back Togekiss was training nonstop.
You can imagine how good the training atmosphere was.
Natsuhiko was delighted and had absolutely no intention of stopping them.
With such a "big fat sheep" right here, it would really be a waste of his trip not to fleece it for all it's worth.
And so.
The originally very quiet and peaceful canyon where Kapu-Muu resided started echoing with continuous rumbling.
Growing more and more intense.
The tremors were so strong that the surrounding Pokémon all thought Kapu-Muu had lost its temper again, and they scattered far away.
Though Kapu-Muu is known for its gentle temperament, that doesn't mean it has no temper at all.
How Kapu Village on Ula ula Island got destroyed is hardly a secret.
...
...
Three days later, in the morning as the sun rose.
Natsuhiko stood at the mouth of the canyon with his Pokémon.
He waved toward Kapu-Muu inside the canyon.
Thanking it for its Help over these three days.
Kapu-Muu hovered in the canyon with lifeless eyes.
Radiating exhaustion from the inside out.
Even though Kapu-Muu is a Divine Beast and can continuously draw energy from the surrounding natural environment, it was actually showing signs of fatigue now.
Especially the dark circles around its eyes.
Who knows what expressions the other Island Gods would wear if they saw it in this state.
For Kapu-Muu.
These three days really felt like years dragged out.
Originally.
In its view, Natsuhiko was Helping the Island Gods take care of Cosmog, so as the representative Island God, offering a bit of Help was only right.
Natsuhiko's Pokémon, while all pretty good, were still far behind Kapu-Muu, so how much trouble could special training them possibly be?
And in fact, that was true.
During the first half day of special training, Kapu-Muu was utterly calm and full of self-satisfaction.
Helping them train was a breeze.
Restoring them didn't cost Kapu-Muu much at all.