A few days later, Senju Tobirama and Senju Hashirama returned from their mission. Senju Kyogawa also resumed his previous training.
Because Senju Kyogawa had been easily ensnared by the Sharingan Genjutsu of a One-Tomoe during his previous fight with the Uchiha Clan, Senju Tobirama had devised a plan specifically to help him counter genjutsu.
The most important part of this plan was chakra.
Fortunately, after using Thou Shalt Not Die, Senju Kyogawa discovered that he could absorb chakra after all. He could only absorb a very small amount, but at least he now had the possibility of using ninjutsu.
As for why Senju Kyogawa had been unable to use chakra before, Senju Tobirama had come up with a reasonable explanation.
As a future scientist-in-the-making, Senju Tobirama was already beginning to show a talent for research.
Back when Senju Kyogawa couldn't absorb chakra, Senju Tobirama had taken some of his cells for experiments.
Now, Senju Tobirama had taken some more of Jingchuan's cells.
By comparing the two types of cells, Senju Tobirama had finally found the problem—
Previously, Senju Kyogawa's cells had metabolized too quickly. They were usually metabolized before they could absorb enough chakra. The cycle kept repeating: cells containing chakra were either metabolized or blocked by cells that hadn't produced chakra.
As a result, Senju Kyogawa's chakra pathways had become completely blocked.
Now that Senju Kyogawa could use chakra, it was naturally because his cells' metabolic rate had returned to normal.
Whenever Senju Tobirama talked about research, his red eyes would shine, and the corners of his mouth would unconsciously curl into a smile. It was clear that he loved scientific research.
"But I still haven't figured out what caused your cells' metabolic rate to change, little brother." Senju Tobirama sighed. He had been troubled by the matter for days.
Hearing this, Senju Kyogawa couldn't help thinking about what had changed before and after his injury.
Before he was injured, Senju Kyogawa's body would usually run Healing Jutsu on its own. But after using Thou Shalt Not Die, he hadn't used Healing Jutsu on his existing wounds, so he had naturally stopped running it throughout his body.
Senju Kyogawa shared this theory with Senju Tobirama.
Senju Tobirama and Senju Hashirama both knew that he had been unable to use chakra before. So the only explanation for the "Medical Ninjutsu" he had used in the past was that it was Senju Kyogawa's unique talent—a skill that didn't need chakra to function.
But neither Senju Hashirama nor Senju Tobirama had spread the word. They trusted their little brother and didn't want their words to become a blade that could hurt him.
Senju Tobirama pondered for a moment, then quickly accepted the explanation.
"That would mean your Healing Jutsu is very likely connected to it."
"Your Healing Jutsu is different from ordinary Mystical Palm Technique. Most Mystical Palm Technique focuses on stopping bleeding and using chakra to replenish the life force lost from wounds. Only a small portion focuses on what your Healing Jutsu does—stimulating cells to divide and regenerate."
"However, medical ninjas generally don't run Medical Ninjutsu throughout their bodies all day. So even those who focus on stimulating cell regeneration don't end up with cells that metabolize too quickly..."
As soon as Senju Kyogawa heard Tobirama's explanation, he understood. So his inability to use chakra had been his own fault...
Senju Tobirama pondered for a while longer, then grew serious and asked Senju Kyogawa:
"Kyogawa, do you know that having your cells metabolize too quickly isn't a good thing?"
Senju Kyogawa nodded.
Senju Tobirama continued:
"Rapid cell metabolism can provide more physical energy, but everyone has a limited number of cell divisions. Each time your cells metabolize, they consume some of your existing life force."
Senju Kyogawa was shocked. So keeping Healing Jutsu running all the time had been a downright suicidal thing to do.
Seeing Senju Kyogawa's face turn pale, Senju Tobirama knew that he had taken the warning to heart. He softened his tone and continued:
"Although the Senju Clan has more life force than other shinobi clans, rapid cell metabolism isn't a sustainable solution. Do you understand?"
Senju Kyogawa nodded repeatedly. He now understood just how reckless he'd been.
In this Warring States era, where the average person lived to thirty, Senju Kyogawa had dared to squander his own life force like that. Was he trying to live too long?
If Senju Kyogawa kept wasting his life force, he might not die on the battlefield—he might die from his own Healing Jutsu.
Senju Kyogawa's face was still pale. The thought that he had nearly brought about his own end filled him with fear.
Tobirama really was the best. If not for him, Senju Kyogawa probably wouldn't have known what killed him until the day he died.
Would the lifespan he gained from converting Cuddle Points increase if Senju Kyogawa stopped using Healing Jutsu?
Senju Kyogawa decided to give it a try.
Sure enough, just as Senju Tobirama had said, his lifespan conversion value increased after he stopped using Healing Jutsu.
Sure enough, too much of anything is a bad thing. Senju Kyogawa couldn't help but sigh.
Once they had figured out what was going on with Senju Kyogawa's chakra, Senju Tobirama began drawing up a chakra training plan for him.
The first step was to test Senju Kyogawa's chakra nature.
Senju Tobirama handed Senju Kyogawa a dull gray sheet of paper.
Senju Kyogawa had never seen paper like it before, so he asked in confusion:
"What's this, Tobirama?"
Senju Tobirama explained:
"This is Chakra Induction Paper. If you send chakra into it, it'll reveal your chakra nature."
As he spoke, Senju Tobirama took out another sheet of Chakra Induction Paper and infused it with chakra. The paper immediately became soaked, with water dripping from it.
Senju Kyogawa carefully channeled chakra to his fingertip, then sent it into the paper.
The next second, one corner of the paper became wet. It was nothing like Tobirama's, which had been completely soaked.
Pinching the damp corner of the paper between his fingers, Senju Kyogawa asked in confusion:
"Why is only one corner of the Chakra Induction Paper wet...? It's completely different from yours, Tobirama..."
Senju Tobirama smiled and ruffled Jingchuan's white hair as he explained:
"That's because you have too little chakra. If you had as much chakra as I do, the paper would be completely soaked."
"But... yours is water-natured like mine, huh? That makes things easier. From now on, I'll take care of all your chakra training."
Senju Tobirama thought for a moment. "So we'll still need to train your ability to break genjutsu first..."
Senju Kyogawa could tell from Senju Tobirama's serious expression that his chakra training wouldn't be easy.
Senju Kyogawa was on the verge of tears.
Before you continue