While deafening cheering echoed through the arena, no one in the Kage viewer stand said anything as they were still looking at the unconscious Karin in disbelief. Or, to be more precise, they were looking at the slowly fading seal on her belly.

The first person to recover from their shock was Tsunade, whose head immediately snapped towards Yuna, who currently had a smug expression on her face.

"What the hell was that, Yuna!?

"

Yuna's facial expression became even smugger when she heard Tsunade's question, and moments later, she started explaining.

"That was the accumulation of multiple years of research. First, Natural Energy. I have been researching Natural Energy for quite some time now and noticed relatively early that it doesn't work well with seals. If you try to incorporate Natural Energy into a seal, it will turn into stone. Still, I am not someone who gives up easily, so after a few years of trial and error, I finally managed to do it: Seals that attract and store Natural Energy.

"

While Tsunade looked at Yuna in bewilderment, Gaara and Mei had no idea what she was talking about, which wasn't too surprising. Natural Energy and Senjutsu are pretty much unknown to most people, after all. Yuna was unbothered by their blank stares and continued her explanation.

"Second, Orochimaru's curse.

"

She heard an angry growl from Tsunade but ignored that as well.

"Or, to be more precise, the way the seal absorbs Natural Energy and infuses it into the human body. I wanted to combine my seal, which can store Natural Energy, with Orochimaru's that infuses into a human body while attracting even more energy. Naturally, I didn't want to have anything to do with the way Orochimaru's seal distorts the user's body when used, so I had to modify it quite a bit. This way, it could instantly grant the power of sage mode without all that holding still nonsense. But, there was a problem.

"

Before Yuna could continue her explanation, Tsunade opened her mouth and started speaking.

"In input of Natural Energy must still be regulated, since if someone were to absorb too much, they would turn into stone. So, only someone who can already activate Sage Mode can use the seal. As far as I know, that would mean that only one person could currently use it.

"

Yuna nodded in approval at Tsunade's analyses and continued her story.

"Correct. I was stuck with that problem for quite a while, but I actually stuck gold around a month ago.

"

As she said that, a small vial with transparent liquid appeared in Yuna's hand.

"Third, Hero Water.

"

Now, everyone in the room, except for Hinata, looked at Yuna in confusion, causing her to chuckle.

"I'm not surprised that you don't know about it. Hero water is the secret weapon of Takigakure. The one who drinks it will burn his life span in return for a massive, temporary increase in chakra quality and quantity.

"

Tsunade wanted to ask how Yuna got her hands of Taki's secret weapon, but then she remembered the young brown-skinned woman that had been running around the Uzumaki compound and asking people perverted questions.

'If I remember correctly, she appeared about a month ago. Oh well, that's Taki's problem, not mine.'

Although Yuna just explained the effects of Hero Water, that still didn't explain how exactly it helped her in the creation of that seal, so Yuna continued talking.

"So, I analyzed the Hero Water and its source to find out how the process to turn lifeforce into chakra worked and how to replicate the effect using seals. Then, I modified the process so it burns excessive Natural Energy instead of life force. And finally, I had to combine all of that into one seal that I naturally made to look like the Uzumaki clan symbol. Oh, and on a side note, Karin could have used Ninjutsu and Senjutsu as well, but against Lee's speed, that would have been rather pointless.

"

Everyone was in a slight daze when Yuna finished her explanation. A glint passed through Yuna's eyes as she opened her mouth again.

"The final product produces a combination of a weakened Sage Mode and the state someone is in after drinking Hero Water. I'm calling the seal: Ultimate Supreme Uzumaki Sealing Ar...

"

"Yesyesyes, it's a very long, cool, and intimidating name. We do not doubt that.

"

Yuna was just about to proclaim the name of the seal when Hinata interrupted her mid-speech. Yuna glared at Hinata, but she pretended not to notice Yuna's glare.

'Seems like I have to punish a little girl tonight. Now that I think about it, Karin didn't say the technique name either. It seems like I have to not punish another little girl tonight.'

"Whatever, you mortals aren't worthy of hearing its true name anyway.

"

Meanwhile, Tsunade got out of her daze and realized what kind of implications such a seal would have. Just imagine if every single shinobi in Konoha could go into a pseudo-Sage Mode when they needed to. Before Tsunade could issue those thoughts, Yuna shook her head and started speaking again.

"I know what you are thinking, but it is not that easy. That seal still has a lot of flaws. No security flaws, mind you, but other problems. For example, if I were to inscribe it on your body, it wouldn't work because the chakra I used to write the seal would clash with yours and the Natural Energy the seal would try to store. So, for now, it can only be used by people who have the skill to inscribe it on themselves. Additionally, if multiple people have seals on them that suck up Natural Energy, then it will take much longer for the seals to be fully charged. Well, in the end, this one is just a proof of concept. Now it is time to refine it, so it matches my standards.

"

Mei and Gaara both sighed in relief when Yuna finished listing the seal's flaws. Their villages might be allied with Konoha, but if every single one of Konoha's shinobi could power up like Karin just did, then they might as well surrender immediately.

However, Tsunade wasn't sure if she should be happy or sad about the apparent flaws of the seal. On the one hand, the number of mission casualties would probably drop to zero with that seal. On the other hand, if their enemies could get their hands on that seal, fights between shinobi would be even more destructive and would probably level the Elemental Nations.

Naturally, Yuna was aware of the danger of that seal as well, so her research would,

"unfortunately

", get stuck at the problem that shinobi had to draw the seal on themself.