Barren Land of Rivers

[This bonus chapter was once again sponsored by the honorable Godphaze. The second one thus far.]

Tanigakure faced a sudden shortage of missions. An eerie silence had enveloped the Land of Rivers. The population was sparse, and the flow of information and resources had slowed down.

Merchant caravans were found with their wares left behind with their vendors nowhere to be seen. The shinobi guarding those caravans had all but disappeared.

Chuunins and genins had been disappearing in the dozens. Only jounins were confident of moving around without suddenly disappearing.

Even foreign shinobi were disappearing. Missing-nin under the rank of jounin also disappeared without any signs of battle.

An unnerving chill wafted about the valleys of the Land of Rivers like the grasp of a vengeful spirit.

Rare sightings of a silver-haired figure had been spreading. A being who could not be sensed by conventional means had been haunting the lands.

So much so that Tanigakure was put on high alert.

***

"Another batch of civilians arrived," A Tani-nin said, reporting to one of Tanigakure's jounin.

The jounin, Kaba Kei, was the kunoichi in charge of overseeing the people who went in and out of the village.

She was an experienced sensor, capable of weeding out shinobi who had hidden their chakras. 

"Are they at the usual spot?" Kei asked the reporting genin.

The Tani-nin nodded, "Yes,"

Upon hearing this, Kei nodded and left.

It took her only a few minutes to travel through the village where she was met with an elevated field. When she arrived, she secretly washed the civilians with her chakra field, draping them with her senses.

"Hmm,"

Kei's eyes narrowed. She noticed a significant chakra signature from within the group. 

'Their under a Tranformation Jutsu. It doesn't seem like they've noticed me...'

Walking in front of the civilian group, Kei noticed a cloaked, middle-aged man near the center of the group. He had a rough look, with short brown hair and an uncannily gentle gaze.

His eyes seemed to shimmer with hope.

'He should be the one I noticed,' Kei glanced at her fellow Tani shinobi watching from the side.

Recognizing the signal, they got ready to fight.

With this, Kei left an afterimage and slashed her tanto straight into the 'middle-aged man.' Her strike was swift, leaving all of the civilians unaware of her movement. They were all influenced by a Genjutsu that dulled their senses.

"Hap!"

Her tanto slashed through the man's neck without any resistance. Kei then rushed back to her position, wary of a sudden counterattack.

However...

"Huh?"

There was no counterattack. The middle-aged man simply fell to the ground, bleeding from the cut in his neck.

He was as good as dead.

Kei was shocked. This was the first time a shinobi of such chakra levels did not even fight back. She made a mistake.

Unfortunately, what was done was done.

It was better that a potential threat was never given the chance to become one, especially in these dire circumstances.

With her eyes, she signaled the other Tani-nin to deal with the body. Turning away, she took one last glance at the dead shinobi and got rid of the unnerving grasp on her heart.

Her task had been completed. There was nothing else to worry about.

No one was aware of the gaze that had been observing them the entire time.

***

'How ruthless,' Suguru thought as he deactivated his Kaisugan.

Currently, Suguru was perched atop a cliff overlooking Tanigakure. His Kaisugan's range was just about enough to see into a part of the hidden village.

Gathering information was a delicate task, and Suguru did not want to waste the opportunity he had been handed.

'They've stopped sending out their chuunins and genins without a jounin guardian...' Suguru pursed his lips, 'Unfortunately for them, they can't maintain that state for long.'

The world continued to move while Tanigakure holed up in their village. They were too wary of Suguru's actions.

'To be honest, that's fair.' Suguru thought.

Over the course of the last few months, he had been devouring a large amount of chakra. From January to April, Suguru had been using Dark Release nonstop.

So much so that he had to extend his goal further: instead of just thirty Shadow Clones, he was going for double that. To have the chakra reserves to create sixty stable Shadow Clones meant that he would have a lot of leeway.

Currently, Suguru could make thirty-four stable Shadow Clones.

'I've also figured out the stable Shadow Clone equation.' Suguru noted to himself.

As an oversimplification, the equation went like this:

• The base chakra requirement for a 'stable Shadow Clone' shall henceforth be called the Shadow Constant, K. Where K is the amount of chakra used per second.

• The Shadow Constant thus dictates how much chakra one needs to create a Shadow Clone that will last for one second without any interference.

• Suppose that a shinobi uses C amount of chakra, then the duration, t, of a shinobi's clone could easily be solved using the equation, [t = C/K]

Using the stable Shadow Clone equation, Suguru could properly quantify an individual's chakra reserves.

He just had to measure how long the individual could keep a Shadow Clone active. After all, using a little derivation, he got an equation that could solve for someone's total chakra reserves. The equation — where Suguru had wracked his brains to figure out the right units — was as follows:

Total Chakra = (Jutsu Cost)(Power)(Chakra Quality) + ½ (Jutsu Cost²)(Shadow Constant)

In other words, [T = jPQ + ½ j²K].

[A/N: It's the Law of Conservation of Energy for those who find the equation familiar.]

Where jutsu cost was simply the amount of chakra used, power was self-explanatory, and chakra quality was the energy for every unit of chakra released.

'...I hate everything about this.'

Having to adjust to this world's characteristics meant that he had to make a lot of deeper assumptions about what was what when it came to chakra. Furthermore, although he had the equations, he still could not perfectly calculate someone's total chakra.

After all, what the hell was chakra quality? How could he measure that? The Kyubi probably had a staggeringly high chakra quality. But again, how exactly was he supposed to measure that?

Suguru's head was hurting.

He had the vague idea of first identifying the difference between a shinobi's blue chakra and a Bijuu's red chakra. However, he didn't have any test subjects at the moment.

Suguru shelved his initial thoughts in hopes of utilizing them more in the future.

"Sigh,"

With that said and done, the Suguru who had been looking at Tanigakure exploded into a puff of smoke. The real Suguru who was hiding a distance away, received the relevant memories.

'So we were coincidentally thinking the same thing. As expected of myself...'

Suguru closed the notebook he had entitled, [Chakra Dynamics], and slammed his head on the table.

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