By the time Kenichi Amemiya carried out the latest batch of thermobaric explosives, the lab was empty.
Orochimaru was gone.
Kenichi wasn't surprised. His teacher was still an active ninja, after all. There were always side projects, secret visits, experiments or "errands" that had nothing to do with him.
Compared to wondering what his teacher was up to, he was much more interested in what would happen when thermobaric fuel met chakra.
Obviously he couldn't test that inside the lab.
If he blew up another lab, his entire net worth would go straight into repairs, and he'd be back to being a broke researcher with dreams and zero budget.
So he left the base and found a secluded mountain valley with a lake—
quiet, remote, and, most importantly, far away from anything he'd miss if it accidentally evaporated.
"My natural chakra affinities are fire and lightning… but once you learn nature transformation, switching elements is just a matter of control."
Kenichi pulled out his personal lab notebook.
This experiment might end in failure, but the data would matter later. Everything needed to be logged.
He'd prepared twenty samples of thermobaric fuel.
Each sample: exactly 100 grams.
Same weight, same composition.
If the fuel was identical, then any difference in explosive power would be caused purely by chakra nature—
a classic controlled-variable experiment, just in "ninja world" packaging.
He picked up the first sample.
[Experiment Log]
Sample No.1 – infused with lightning-nature chakra equivalent to Chidori.
Result: fuel became extremely unstable; detonation triggered almost instantly during fusion.
The explosion slammed into the massive Rashōmon gate he'd summoned as a shield.
Kenichi squinted at the smashed gate and scribbled more notes.
[Log]
Compared to baseline thermobaric blast, output increased significantly.
Monitoring seals on Rashōmon detected a large surge of electrical discharge.
He frowned.
Lightning-nature chakra… really didn't mesh well with the fuel.
It acted more like a built-in detonator than a booster.
Sure, the explosion came with a massive electric shock, but anyone tough enough to survive a thermobaric blast head-on…
would probably treat this level of current as a full-body muscle massage at best.
Next was fire.
[Experiment Log]
Sample No.2 – infused with fire-nature chakra.
Result: like lightning, extremely unstable. Fusion immediately triggers a violent explosion.
[Log]
Rashōmon's damage is clearly worse than Sample No.1.
Fire-nature chakra appears to amplify the reaction, or it's accelerating some deeper chain reaction inside the fuel.
Kenichi rolled his shoulders.
Thankfully, he'd already learned the Rashōmon summoning from Orochimaru.
It wasn't as versatile as other summoned beasts—basically pure defense, and only in a fixed direction—but it was still incredibly tough.
And today, incredibly abused.
"Yeah… turns out chakra fusion isn't exactly plug-and-play," Kenichi muttered.
But he wasn't discouraged.
He tested the other elements one by one.
Water-nature chakra: completely useless.
It soaked the fuel, ruined it, and he had to dry and remake it. A pure loss.
Earth-nature chakra: actually made the explosion weaker.
Sure, some extra rocks and dirt got thrown around, but tactically it didn't add anything worthwhile.
Yang-nature chakra: no observable effect at all.
At least, nothing his seals or eyes could detect.
Wind, though…
Wind gave him a surprise.
[Experiment Log]
Sample with wind-nature chakra: fuel disperses more widely, but blast propagation speed increases sharply.
Kenichi tapped his pen on the notebook, thinking.
Water and earth could be discarded for now.
But fire, lightning, and wind all had some kind of positive effect.
The problem was still the same:
How do you get the fuel and chakra to fuse stably, without turning everything into an instant landmine?
"Let's try Sage Mode."
Kenichi steadied his breathing.
Natural energy swirled toward him.
Frog-like markings crept around his eyes as he entered Sage Mode.
The moment he switched to senjutsu chakra, the nature of it changed.
Lightning-nature sage chakra:
infusing it into the fuel made the explosion unleash visible lightning arcs from within the fireball.
Fire-nature sage chakra:
when that hit the mixture, the explosion's power multiplied several times over.
One of the Rashōmon gates was blown straight through.
This was just 100 grams of thermobaric fuel.
And Rashōmon had excellent defensive power.
For a single small sample to punch a hole in it—
Kenichi couldn't help getting excited.
"As expected… fire-nature chakra really does enhance thermobaric fuel. It's like pouring gasoline on a super-weapon."
The only thing ruining it was the ridiculous instability.
Wind-nature sage chakra, on the other hand, made the explosion… faster.
Much faster.
Normal thermobaric blasts spread at about half the speed of conventional high-explosive detonations.
With wind chakra mixed in, the expansion speed jumped several folds.
That was both good and bad.
Good: the faster it spread, the harder it was for anyone to react and defend in time.
The shockwave would hit like a wall.
Bad: the window for creating and maintaining a vacuum would shrink.
The core "fuel-air" effect of a thermobaric weapon might drop if it expanded too fast.
It was a trade-off.
"So in theory, the ideal combo is… fire + wind + lightning."
He rubbed his brow.
"Maximum damage, maximum effect. In theory, anyway."
But theory was the easy part.
The hard part was getting three different chakra natures to work together without everything exploding in his face.
Mixed-element jutsu did exist, sure.
But truly fused ninjutsu were rare and insanely difficult.
Jiraiya's Sage Art: Goemon was strong, but that relied on three people combining their elements, not one person fully merging natures inside their own chakra network.
In Kenichi's opinion, Hashirama was the real standard for fusion ninjutsu.
Water + earth → Wood Release.
But knowing the theory and reproducing Hashirama's talent were two very different things.
Different chakra qualities, different bodies, different souls…
He couldn't just "do it because Hashirama did it."
"Yeah… this is a problem."
He stared at the scorched cliff and half-destroyed gate, then suddenly got another idea.
"…What if I don't try to fuse the chakra inside my body?"
His eyes lit up a little.
"What if I store three different chakra natures separately… in containers? Then embed those containers into the fuel, and trigger them simultaneously at detonation."
No perfect fusion.
Just brute-force parallel activation.
Not pretty. But if it worked, that was enough.
Like bad spaghetti code that somehow compiled and ran in production. As long as it did what he wanted, he didn't care if the underlying logic made other scientists cry.
He put away the remaining thermobaric fuel carefully.
The concept was ready, but there was still a key bottleneck:
What could safely hold chakra?
Chakra metal was ideal.
But also insanely expensive.
"Maybe I should try using explosive tags as containers…"
He looked at the samples in his hands and exhaled slowly.
This line of research was going to get seriously dangerous, seriously fast.
Which, in his world… usually meant he was on the right track.
Note: If you're interested, you can read up to chapter 99+ at patreon.com/nakai01. Don't forget to give a power stone for many bonus chapters.