Training under the Second Hokage wasn't what I expected.
Tobirama was a scientific ninja through and through. He assessed me first, marked my stats, and created a regulated training plan focused on every aspect—tailored precisely to my future path.
Which was honestly kind of cool. Everything was quantized, so training felt like leveling up in a game. I really didn't think anyone else in this world trained like this…
Tobirama didn't talk much unless he had something important to say. Which, to be fair, made everything he said feel ten times more important.
Add that to his always serious looks and never being caught lacking—I seriously suspect him of aura farming.
At the moment, we were standing in a shaded training ground behind the Hokage estate—an area no one really used anymore, which made it perfect for the kind of experiments I had in mind.
"The jutsus you have created. Let's start there," Tobirama said, arms folded behind his back.
"Sure. The Rasengan, Rasendan, and Lucid Horror Genjutsu were the ones I wanted to discuss today anyway."
He raised an eyebrow. "Go on."
I took a breath, then began. "So, the Rasengan was inspired by the idea of compression and rotational force. It doesn't need a nature transformation—just raw chakra manipulation. It's purely about control. Perfectly molding chakra in a spherical rotation until it's dense and sharp enough to destroy."
He nodded, not interrupting, but I could tell he was taking in every word.
"The Rasendan," I continued, raising my two fingers like a gun, "was born from the same principle. I wanted a projectile version. So instead of palm contact, I condensed the Rasengan into a much smaller orb—less chakra, faster deployment. It doesn't have as much raw power, but the speed and range make up for it."
"Hmm," he hummed. "That kind of miniaturization… requires insane control. And the increase in practicality is also massive."
I smiled faintly. "That's what I have."
"And the Genjutsu?" he asked.
"Lucid Horror is a derivation of Hell Viewing. I was studying the jutsu given to me by Tsunade, and suddenly thought—showing someone's greatest fear might actually be capable of bringing down even the mightiest shinobi. Everyone has fears… people they want to protect dying, and more…" I said, hands behind my back now.
"But I didn't like the sudden jump-scare method. Instead, I wanted a slower build—something psychological. So I layer in memories, regrets, guilt… all the tiny things that form the base of a person's fear. Then escalate."
Tobirama's sharp eyes didn't blink. "That's… extremely advanced for someone your age."
"I know. I made it for that reason. Most shinobi can't fight what they don't understand. If their own mind turns against them, the fight is over before it starts."
He didn't say anything for a while. Just stared at me. I thought maybe he was trying to find a weakness in my logic.
Instead, he finally said, "The concept is terrifying. But it's very… efficient. Less chakra. More effect."
"Exactly," I said. "It doesn't rely on brute force. Just timing and precision. The target's own mind does the heavy lifting."
"You'd make a good spy," he muttered.
I grimaced. "Let's not go that route. I would rather quit being a shinobi."
Tobirama let out a low chuckle. The first one I'd heard from him.
Then, without warning, he asked, "Tell me something, Inaba. When you first started learning medical studies, your progress was… underwhelming. Tsunade told me you struggled for a while."
I paused.
He continued, "Then one day, it was like a switch flipped. Suddenly, you were absorbing information at a frightening pace. Not just medicine—but across the board. I was curious about that."
I looked at him for a moment, then smiled. "Ah. That."
"I want to hear it from you," he said. "What changed? Of course, if there's some secret, you can choose to keep it. Intelligence is important for shinobi."
"Well, no point hiding it." I tapped my temple lightly. "I enhanced my brain."
Tobirama blinked once. "Come again?"
"I used my chakra control to enhance my brain functions—focus, memory retention, processing speed, everything. The idea came from chakra enhancement. If strength can be enhanced, why not the brain?"
He stared at me, a long pause stretching between us.
"…You enhanced your brain with chakra," he repeated flatly. "And it actually worked?"
"Perfectly," I said. "I use it all the time. Helps with studying, analysis, decision-making. Basically everything."
"No one… in history, as far as I know… has successfully done that."
"I figured as much," I said. "Chakra control was something I never actually had to train for. The first time I extracted chakra, I could already control it better than the instructor at the Academy. And this enhancement falls right under my strength: chakra control."
Tobirama exhaled slowly and rubbed his temple. "You're casually telling me you created a jutsu that modified your own brain like it's nothing."
"Well, it's temporary, but yeah, pretty much I guess."
"And you didn't think to keep it a secret?"
"Honestly? I thought telling you would be the better option. Sure, you wouldn't press me to reveal it, but you wouldn't trust me as much if I kept it hidden. Besides, no one else can copy it. Chakra control at this level isn't something you can fake."
He laughed again. A short, sharp sound. "You really are a piece of work."
"Thanks?" I said uncertainly.
He looked back at me, serious again. "You're not just a prodigy. You're… a problem solver. A creator. That's rare. Most people train to be stronger. You train to be better. I like that. We are quite similar in that aspect. That's why I took you as my disciple—not because you're Tsuna's boyfriend, if that concerns you."
I felt a strange sense of pride rise in my chest. Not the cocky kind. The quiet kind—the kind you feel when someone you respect finally sees what you've been doing all along.
"So, what now?" I asked.
"Now," he said, "we refine everything you've built. Your Rasengan series, your Genjutsu, your chakra control… all of it. You're talented. But I'm going to make sure that talent turns into power. And consider it a privilege of being my student—the forbidden scroll is completely open to you now. Half of it is written by me anyway."
"…Understood. Thanks." Was this the feeling of having a rich father?
He turned to leave. "Same time tomorrow. Bring notes. I want to see what other insane things you've cooked up. I think we'll get along well. And we can also try creating some jutsu together."
"Yes, sir."
And with that, he vanished in a Shunshin.
I exhaled slowly.
This was going to be fun. Tobirama was a legend. If Sarutobi became the ninjutsu professor by learning a lot of jutsu, then Tobirama was the one who created them.
Studying under Tobirama was certainly going to make my future path much easier. Of course, I just had to ensure he doesn't die.
Well, that would be simple. Just tell him that my brain enhancement also grants some prediction abilities, and I was getting some warnings. Kumogakure might have some motives this time.
And that would be it. Tobirama can manage it all after that.