Takara was frustrated and extremely irritated as the worst-case scenario unfolded, and Hotaru indeed detonated the Kinjutsu on her back before succumbing to the gases and losing consciousness.
He severely underestimated her determination, thinking that her fear of death would hold her back enough to fall.
If it had been outdoors, it wouldn't have been a problem since the explosion would have been harmless to Hotaru by hitting its target. However, since she isolated the room where she fell, the contained energy couldn't escape anywhere, and all that remained inside were the remnants of a cracked object in the shape of a thick grayish disc.
The remnants of the Tsuchigumo clan's Kinjutsu that should have been on Hotaru's back.
"The worst part is that I can't use Edo Tensei, and even if I could, it would be useless," the thought infuriated him further.
Since the Kinjutsu was implanted and not part of Hotaru's body, even if he had her DNA and revived her, he would only get a resurrected Hotaru without anything on her back.
He could only settle for the remnants in his hands and try to study them as best he could.
"What's strange is that it doesn't react to chakra. Did it become completely useless?"
Takara examined the remnants of the disc, but no matter how he looked at it, it seemed to be some kind of ordinary mineral that would be found in a cheap market. The only remarkable thing was its hardness, seeing how it resisted the explosion capable of ending a large ninja village confined in a small room.
"Wow, it's been centuries since I've seen such a good natural energy gem," commented Katsuyu on his shoulder, sounding surprised. "It's a shame it got damaged so much, but you could still make use of it."
Natural energy gem?
"Just like there's chakra metal, there are also natural energy gems," Katsuyu continued to explain as she saw that she had piqued Takara's interest. "They are extremely rare. The two largest ones I know of are hanging from the necks of the White Snake Sage and the Toad Sage, but it took centuries to acquire them."
"What's the utility of these gems?" Takara asked.
"They collect natural energy, and if implanted in a body, it will become a passive vessel for natural energy. But this method is crude at best because unlike Sage Mode, natural energy doesn't directly fuel the user's abilities. It's more like creating a living weapon."
"But you said I could make use of it? I don't think you want me to implant these fragments, do you?"
"Of course not!" Katsuyu looked horrified. "That would be like Jiraiya's case or worse, completely unacceptable. What you have to do is polish and combine the gem shards with parts of your equipment, like the mask you use or the needle-shaped sword."
Takara understood what she meant.
"Would it be like creating equipment with chakra metal but the equivalent for natural energy?"
That would be... quite potent if his estimation is correct.
"Exactly!" Katsuyu crawled down his arm to get a closer look at the fragments. "The toads mainly use staffs during their Sage Mode to fight, while the snake's Sage Mode is more focused on ninjutsu employing the environment. I think we can leverage your skilled craftsmanship and my knowledge of their properties to make some interesting pieces."
Takara was still thinking about the living weapon part.
"Would it be possible to make a puppet with these fragments?
If he could make a powerful puppet with Senju wood, chakra metal along with natural energy gem fragments, and then move on to using Chiyo's technique to infuse life energy...
"No, you'd need at least three times more than what you have now, and it's possible you won't see another natural energy gem like this in your lifetime," Katsuyu crushed her contractor's idea unknowingly. "I think it's best that you don't work on them for now. You'll have a better idea of how to use them when we start your senjutsu training and you feel the natural energy."
Takara agreed with Katsuyu, given that he had a limited number of natural energy gems; it would be best to wait until his understanding was more elevated.
"Hmm?" Takara looked at a screen on a mechanical arm that deployed from the floor. "It seems I found my target."
Katsuyu looked curiously at the image of Utakata on the screen, lounging on his side with his head propped on his hand while blowing bubbles in a clearing by a small stream.
"Is he an enemy?"
Takara shook his head slowly but didn't take his eyes off the jinchuriki.
"A prey."