Nobody would expect to be surprised by a stranger talking to them... on the moon. Hearing the voice, the girls instantly turned around, ready for a fight, and then...

Konan furrowed her eyebrows in astonishment, "Yuriko? What are you doing here?"

"Hello, Konan. I work here," Yuriko answered with a small mischievous smile before she turned towards Rei, "Hi, boss. I see you finally decided to show them around?" She asked.

Needless to say, even Mei was completely surprised by this turn of events. She helped Rei the most with his projects, yet, she had no clue Yuriko was already on the moon, doing something for him.

The women instantly turned towards Rei, in their eyes a profound question of why Yuriko was the first one to know. As far as they knew, Yuriko was just a subordinate and a ninja of the Village Hidden on the Other Side. Somehow, she being the first to know about such an important project of Rei's was a low blow to their feelings as women.

Naturally, Rei had no clue about this at that moment and as such, he simply shrugged and indifferently replied, "I needed someone capable of using Senjutsu and there was only Tsunade and Yuriko available. But Tsunade was far too busy to involve her, so Yuriko it was." He said, causing Yuriko to pout.

He had no idea what kind of disaster his carefree reply just saved him from.

"Why would you need a Senjutsu user?" Tsunade curiously asked.

Rei grinned and pointed at the necklace with two seals on her neck he gave her before they teleported, "These seals are supposed to provide oxygen and ensure you will not be crushed from inside out due to vacuum."

All four of his women except Konan widened their eyes when they heard what could have happened to them. They knew what a vacuum was. It was important for high ranked ninjas to know because the two pinnacles of the Wind Manipulation were invisible wind blades, people who chose this way focused on density and compression, and then there was vacuum Jutsu, which focused on getting air out of certain spots, creating a vacuum and then weaponizing it.

That said, they never thought about what is outside of Elemental Nations, much less what is outside their planet, so neither really put many thoughts into the possibility of a natural vacuum being in space.

Natural vacuum... such a term was honestly laughable. Knowing how devastating vacuum Jutsu were, the girls could only wryly grimace at the thought of an air-less state like that existing naturally.

"So, without this," Tsunade patted the pendant on her neck, "we would instantly go squelch?" She asked in trepidation.

Rei grinned and wordlessly pointed at Yuriko, more precisely, her neck area that had no necklace. She actually wore a quite loose shirt and shorts. Unless the seals were tattooed into the part of her skin covered by her clothes, which was a ridiculous idea because the seals were not useful enough to make them permanent and hook them on her chakra system as was necessary with tattooed seals, or drawn directly on her clothes, which was unreliable as heck when it comes to seals that have to function 24/7,... then Yuriko now stood in a vacuum without any protection and was just fine.

"While Tsunade researched Senjutsu itself, I was more interested in nature energy," Rei started explaining. He was not about to tell them his idea came from what he saw in anime during his last life where Naruto without any protection could survive on the moon. That would be ridiculous. Rei naturally had a good excuse for his knowledge. "I found out, nature energy can strengthen the human body, not unlike what it does to the chakra beasts. That led me to a small realization." Rei meaningfully looked at his girls, "we are still wary of the vacuum Jutsu because they are the strongest crushing force our world knows. There is no Jutsu as devastating as these, which is the reason why the Wind was dubbed the offensive element. The only good thing about the vacuum Jutsu is their small area of effect. Yet... how do we know it would work on us when we always evade these out of a healthy dose of respectful fear?"

"You aren't saying you did something as crazy as trying out what would happen to you if a vacuum Jutsu hit you, are you?" Konan unamusedly asked, inwardly feeling a bad premonition telling her she was most likely correct.

Rei turned towards Konan and sheepishly laughed while rubbing the back of his head, "Well... yeah?"

"Dammit, Rei!" Konan sighed and started to rub the bridge of her nose.

Seeing that his other wives also started to narrow their eyes at him because he did something stupid... again, Rei decided to continue with his explanation and hoped they would just forget about the matter.

"I absorb Nature energy into myself and use it to directly strengthen my body for decades now. Honestly, the vacuum does nothing to me." Rei said and gestured that he did not wear the necklace with the protective seals either. "Yet... there are some attacks that can do me harm," Rei glanced at Konan and Tsunade, "despite the force behind them being weaker than what vacuum can exert. After that realization, I found out that nature energy works as a kind of a counter-force against vacuum. And Senjutsu users use nature energy too, hence..." He gestured at Yuriko who still stood in her initial spot.

"Oh," Mei nodded and took the necklace off, stuffing it into her pocket. "Then we should be fine, no? We have our pets, after all!"

"Ah," Konan blinked, "So that's what you are trying to tell us." She understood, "We might not be Senjutsu users but thanks to our bijuu that were made thanks to the nature energy in your dimension, we should be fine."

"Yeah," Rei sighed, "Then again, you are lucky it also makes you capable of surviving without oxygen, Mei. I really did not expect you to just yank the protective necklace off your neck." He shook his head before mumbling, "And they call me reckless..."

"So, should we proceed to the base?" Yuriko interjected. As amusing as watching the interaction between Rei and his wives was, she still had some work to do.

"Base?" Pakura turned towards her, "Rei ordered you to make a base here?" She looked around the barren, rocky terrain without anything interesting in it, not understanding why exactly they should care about the moon. It was a good place for a bolt hole that nobody could find, but other than that? She thought it was a waste of resources.

"Of course!" Rei put his hands on his hips in a self-important manner, "We already have Uzushio and the Village on the Other Side under our rule. Why not add a Village on the Other Side of the Moon there too? It might seem like nothing special but the moon has a lot of metal deposits. Metals that may or may not be even stronger than chakra metal."

"Now we are talking!" Ringo grinned, her eyes sparkling at the thought of metal stronger than chakra metal.

The opinion about the new base on the other side of the moon quickly shifted to being a favorable one once Rei explained why exactly he chose the moon.

Alas, Konan was not easy to fool.

"Plus, there should be Kaguya Otsutsuki sealed inside of this ball of rock. Isn't that right, Rei?" She smirked, giving him a knowing look. "Are you perhaps trying to get a new girl?"

Rei just shrugged, not expecting to be able to hide Kaguya's existence. After all, he did tell them about her. Then again... "That doesn't really depend on me, now, does it?"