Since the spar was over, Kaida turned to the elders and Fugaku and asked, "Fugaku-sama, I have a class to attend at the hospital. Can I go now?"
"Yes, you can," Fugaku said, and the elders nodded their heads.
Hearing that, Kaida bowed his head and quickly used the Body Flicker Jutsu to go to the hospital. He had become a general practitioner some time ago and had also learned all the advanced jutsu, especially poison creation and cures, as well as the chakra scalpel. In these two areas, he could already be considered an expert.
Okay, maybe poison creation could be excluded from this, but the chakra scalpel was something he took pride in. The only other person who would be this good at this jutsu is still under Konoha, and he has not yet become the future villain. Also, he hasn't gotten the extra resources he would have received if he had joined Orochimaru.
But now, things have changed. Konoha will focus on him more than Orochimaru would have, so in the future, Kabuto may become much stronger than an elite Jonin and might even reach Kage level.
But that is the future; for now, Kaida's mind was focused on one thing: increasing his strength. After today's spar, that feeling had only intensified. Not only is the future unpredictable, but the strength gap between him and the top ninjas is also very wide—but achievable.
And the fastest way for Kaida to increase his strength for now is...
'Mitotic Regeneration Jutsu, I have to learn it now,' Kaida thought as he reached the hospital.
He directly went toward Mitsuru's office.
"Sensei," Kaida said, knocking at the door.
"Come in," Mitsuru said.
"So you finally got time for learning? I thought you would still be busy showing off your strength," Mitsuru asked, a little anger visible on her face.
"What do you mean, showing off my strength, Sensei? I lost the spar. Heck, I lost when the other party was holding back more than three-quarters of his strength," Kaida said, a little dejected.
"Were you fighting an elder?" Mitsuru asked. She knew how strong Kaida was—he was already a Jonin-ranked ninja. Though not very experienced, he still had a huge chakra reserve to compensate for the lack of experience.
"Elder? He was just one year older than me," Kaida said.
"This is your last chance. If you don't give me a straight answer, forget about going back home for the next two days. You will be learning about various medical techniques for two days and nights straight," Mitsuru warned.
"Well, I don't think that is a punishment. Also, I'm sure by now you would have already guessed who my opponent was," Kaida said with a light chuckle. He was not a fool who would underestimate the intelligence of someone from the Nara clan.
"So you really fought against Itachi Uchiha. I've heard quite a few things about him. So, how long were you able to hold out against him?" Mitsuru asked.
"Not much. We fought using only kenjutsu and genjutsu, and even then, I was only able to hold out for 10 minutes before losing," Kaida said meekly.
"Itachi is a genius of the century. It would be a feat in itself for someone two years older than him to match him, while you are actually younger than him. Don't think too much about the loss; try to think about how you can improve yourself," Mitsuru said.
"I was about to ask you about that, Sensei. I have already learned all of the jutsu you asked me to. My operation success rate is also 100%. I have already crossed beginner-level fuinjutsu and will start learning seal master-level techniques in 2-3 days," Kaida said.
"You still haven't forgotten about that jutsu?" Mitsuru asked.
"How could I forget about that jutsu, Sensei? It is one of the signature jutsu of a legendary Sannin," Kaida said.
"But I have already told you, no one knows the advanced version of that jutsu except Lady Tsunade. What we know is one level inferior to that," Mitsuru said.
"That will be enough, Sensei," Kaida said with a smile.
"Huh, looks like you won't change your mind until I tell you the reality of that jutsu. Fine, listen.
The Mitotic Regeneration Jutsu, also known as the Strength of a Hundred Seal, allows the user to instantly heal any injuries they sustain during battle by accelerating their cellular regeneration. It also increases the strength of a person multiple times. But there are many drawbacks to this jutsu. The first and most significant one is accelerated aging and a shortened lifespan. The technique rapidly accelerates cellular division to heal injuries, which can significantly shorten the user's lifespan if overused. Each time the cells divide, the user edges closer to their biological limit," Mitsuru explained.
"I think that is not a bad thing, Sensei. If an injury could take someone's life, isn't it better to lose some years and save yourself?" Kaida asked. He was not that affected by this news, as he already knew about this side effect.
"You are underestimating it, Kaida. Even though Lady Tsunade improved the jutsu to make it useful, the version we have is highly unstable. If activated for 10 minutes, you will lose 1 month of your life, and that effect multiplies. After 20 minutes, you will lose 6 months; half an hour, and you will lose 1 year; and for 1 hour, 10 years of your life. In short, you would be killing yourself every time you activate this jutsu. Also, every time you heal any injury, you will lose another part of your lifespan," Mitsuru said.
"What about Lady Tsunade? How much time does she lose?" Kaida asked.
"One hour—6 months," Mitsuru said with a shrug of her shoulders.
'No wonder she is known as the best medical ninja in the world. She has almost removed the shortcomings of this jutsu. Sadly, I cannot wait for her to learn this jutsu. Heck, I don't even know what will happen in the next five years, let alone wait for 10 years for her to return. I will learn this version for now and modify it when I meet Tsunade in the future,' Kaida thought.
(A.N: Tsunade returns after the Hokage's death, which was when Naruto was 13-14 years old.)
"I still want to learn this jutsu, Sensei," Kaida said.
"Huh, you are too stubborn for your own good. Fine, for the next month, I will teach you everything you need to know before learning this jutsu. As for fuinjutsu, I will tell you the concepts you need to master. Learn them, and we will start the process for you to learn that jutsu," Mitsuru said.
"Thank you, Sensei! You are the best," Kaida said with a wide smile. Mitsuru just nodded her head with a smile and gestured for Kaida to leave. Kaida bowed his head and left the office.
'Oh, I forgot to tell him about the pain part. Well, let it be a surprise for him,' Mitsuru thought with a villain-like smirk on her face. (A.N: Just villain-like, not an actual villain 😉)
Kaida was re-reading some of the books when a nurse came to him.
"Kaida, Mitsuru-sama is calling you in room number 44," she said. Kaida nodded his head and said,
"Okay, I will go now." Normally, the nurse would have to give Kaida the same respect as any specialist, as he was a personal student of Mitsuru herself. But when Kaida heard someone thrice his age calling him "Kaida-sama," he firmly refused and insisted everyone call him by his name. Everyone was actually happy that their new boss was going to be such a humble person.
According to everyone, Kaida was going to succeed Mitsuru as the head of the Emergency Response Department for sure.
Kaida went to room number 44, where he once again saw a familiar scene in front of him. Mitsuru was standing in front of a stretcher, which was covered by a white cloth.
"Sensei, are we once again going to practice on a corpse?" Kaida asked.
Mitsuru smiled and pulled the cover off the body, and Kaida was a little shocked. The person was very much alive and horrified, his hands, legs, and waist tied to the stretcher. Even his mouth was gagged so that he could not make any sound.