Otsutsuki Toneri.
He was a native Ninja bearing the surname 'Otsutsuki', his ancestor being Otsutsuki Hamura, one of Kaguya's two sons.
After sealing their mother together with his brother back then, Hamura took his descendants to the moon, forming another lineage of Otsutsuki-human mixed blood.
Unlike the Ninja World, where the bloodline grew progressively thinner with each generation, everyone on the moon was mixed-blood, so even by Toneri's time, they still retained many Otsutsuki characteristics.
For example, their overly pale skin, their exceptional control over Chakra, and… the innate Byakugan.
Unlike the Uchiha and Hyuga Clans, which developed as branches on Earth, this lunar lineage only inherited the Byakugan traits from Kaguya due to Hamura.
Of course, compared to their earthly counterparts, their Byakugan purity was higher, and their ability to penetrate Chakra Pathways, and other substances was stronger.
So in terms of overall combat ability, this lunar lineage could easily crush the Hyuga Clan.
—Of course, that was assuming all their members were still alive.
It all started after the day Hamura, the Sage of Six Paths' younger brother, died.
Because they were mixed-bloods, they didn't inherit their mother's immortal traits. Although they still lived for many years, their lifespans eventually ended.
Before dying, Hamura had admonished his descendants: "Watch over the Ninja World carefully."
Essentially, he hoped these children would watch over each other with the Ninjas of the Ninshu his brother founded and also monitor the split Ten-Tails.
However, the Ninja World's people's habit of leaving things unsaid inevitably led to misunderstandings.
His descendants split into two factions over the interpretation of his words.
One faction advocated for peace, believing the ancestor meant for them to observe carefully and not arbitrarily interfere in the Ninja World's development until a disaster occurred.
The other faction believed the war-torn Ninja World had already violated Otsutsuki Hagoromo's original intention in creating the Ninshu and should be destroyed.
The main family and branch family couldn't agree and came to blows, resulting in the branch family's ruthless members sacrificing all their Byakugan to create a giant eyeball, the [Tenseigan], and wiping out the main family.
Until now, the moon was still controlled by members of the branch family.
Otsutsuki Toneri was the current head, or rather, the last descendant, of the branch family.
There was no helping it.
When the branch family annihilated the main family back then, they themselves didn't fare well either.
Many clansmen, having their eyes gouged out, suffered Chakra loss and couldn't maintain the long lifespan of Otsutsuki mixed-bloods.
Coupled with too few members to produce healthy offspring, the branch family gradually withered away.
By the time of Toneri, he was the only one left in his generation.
He was even born without eyes, which could be considered lucky or unlucky.
Being the only one left, Toneri wasn't in a hurry to start his 'purification' plan for the Ninja World.
He was quite smart.
Destruction was for creating a new world, but a new world couldn't just have him alone.
So this guy set his sights on the Hyuga Clan on Earth… more precisely, on Hyuga Hinata.
He planned to wait until Hinata came of age, bring her to the moon, marry her, and after destroying the conflict-ridden Ninja World, the two of them would become the new progenitors of humanity.
As for whether he could win, he wasn't too worried.
With that giant Tenseigan, even if only he, the last lunar branch member, remained, he could challenge all Ninjas on Earth.
As long as the Tenseigan was still there, he was invincible under heaven.
Toneri always believed this.
But plans were beautiful, reality cruel.
Before he could happily marry Hinata, someone from the Ninja World came first.
"Intruder?!"
In the castle hidden deep beneath the moon, Toneri suddenly heard his detection system frantically alarm.
At first, he thought the giant Tenseigan had lost control, but when he arrived at the core, he discovered the alarm came from autonomous puppets distributed on the lunar surface.
Though these puppets lacked thinking ability, they could act according to preset programs and make corresponding reactions. Even individual combat ability could easily surpass certain Sunagakure by two streets.
Without sight, Toneri could only press his hand on the core console, linking his innate perception with the alert puppet.
The result was that the next moment, two blazing 'suns' appeared in his 'vision'.
One was smaller, its Chakra emitting a violent and ominous presence.
The other was even more exaggerated.
The energy intensity, almost overflowing beyond his imagination… he had only felt something similar near that giant Tenseigan.
'Were they Ninjas from the ground?'
Toneri instinctively thought, but almost instantly dismissed the idea.
There were indeed some spatial folds on Earth leading to the moon, but finding them required the Byakugan's ability to precisely discern Chakra Flow, like the moon's Otsutsuki.
Moreover, how could Ninjas from the ground be so powerful?!
Toneri was unwilling and unable to believe this.
Fortunately, the puppet acting as his 'eye' soon denied this.
The puppet's 'image capture device' rapidly adjusted to a mode more suitable for the current light, finally allowing Toneri to see the two figures clearly.
Good news, judging by appearance, they were indeed not 'people of the ground'.
Bad news, those who came were 'people of the sky'.
Just by appearance alone, those two looked more like that ancestor than he, a pure Otsutsuki descendant, did.
…
At the moment Toneri's puppet discovered Isshiki and Naruto, they also discovered Toneri.
"This is… a puppet? No, there are actually people down there?!"
A few kilometers of lunar crust couldn't possibly block Naruto's perception, let alone when he was in a 'strengthened state'.
The moment he discovered the obviously man-made object, Naruto fully unfolded his Observation Haki, covering one-third of the moon.
This was already the limit of what he could currently achieve.
Fortunately, although there was life on the moon, it wasn't the huge settlement he had imagined. His and Isshiki's battle probably wouldn't affect too many innocent people.
"Only one person, should be fine… You bastard, stop moving!"
Having only scanned one person, Naruto was about to send this unlucky guy away first, but the Isshiki he was holding wasn't willing.
Having merged with the Ten-Tails, he was much more irritable than before and also strengthened in strength.
Naruto's palm tightly squeezed his head, so he transformed other parts of his body into trunk-like material, directly turning into a tentacle monster and attacking Naruto in his current 'small glowing figure' form.
The wind pressure casually generated by those tree-like tentacles could easily cut through the earth.
Speaking of which, Naruto hadn't expected there to be atmosphere on the lunar surface.
He had originally thought it was just a barren place where birds didn't even defecate.
Seeing Isshiki struggle so violently, and since he himself had entered the [Inversion] state and the accumulated energy needed to be emitted immediately, Naruto had to set aside the discovered 'lunar native' for now.
"It's time to let you taste the power of this move yourself!"
Saying this, Naruto's arm violently used force, flinging Isshiki into space.
The force was considerable, and Isshiki soon moved away from the lunar surface by several tens of kilometers.
This distance was still very close on the cosmic scale, but enough to avoid being affected by the energy.
Determining the distance was about right, Naruto hesitated no longer, gathering all the energy transformed from the previously absorbed super Tailed Beast Bomb into one point, then blasting it toward Isshiki.
"Roar!!"
The flung Isshiki barely managed to adjust his posture, using his newly grown Rinnegan to control gravity and stabilize himself.
Then he felt the energy onslaught filled with destructive aura.
In the past, he would have shrunk and temporarily avoided it.
But now, Isshiki was subtly influenced by the Ten-Tails' will, instinctively abandoning this more reasonable response, instead starting to use gravity to attract nearby floating meteors, hurling them as shells downward.