[Saiyō Residence - 2 years after the wedding]
As time passed Kusuri had slowly shown his capabilities at a rate similar to a normal child's.
Well, an above-average child at least.
He spoke in simple phrases and could simply ask what a word meant instead of having to figure it out from context clues which was good for his sanity. He also started pretending to learn to read, asking even more questions to clear up the gaping holes in his knowledge.
All in all, he would likely be fully literate in a year or so. He wouldn't hide too much of his later progress, as it could be hidden behind his relentless questioning.
At first, his grandparents thought his constant questioning and will to learn was adorable, and, to an extent, they still did, but they also got a touch exasperated with the sheer volume of queries they were being pestered with. Countless instances of "What does _____ mean" or "What does this say" had made it to the point that their grandchild had a vocabulary of a child nearly twice his age. They were a tad bit terrified, but they were also rather proud.
They would've been even more of both if they knew what Kusuri did when they weren't around.
Specifically, he had decided that he would start looking a tad into his new world's resident power system.
One thing he had noticed not long after arriving there, was that he could already feel a bit of the chakra's flow inside his body. It was faint, unsurprising due to how weak he was, but he felt it all the same. He didn't know if it was normal to be able to sense chakra as early as he had, but with nothing to compare it to he filed it under questions for later.
At first, all he would do was meditate a tad every day or so. He did it just enough to form a habit out of it. He didn't see progress very readily, but he frankly hadn't expected to, he wasn't Sasuke or Itachi or any other mind-melting prodigy, he was him. Though he supposed he did have his own advantages.
Eventually, he saw headway. He could sense his chakra rather well, and at the tail end, could even do a bit to move it.
Unfortunately, it took a full year just to do that.
That wasn't entirely his fault, he didn't have that much time to train daily, and frankly didn't want to train constantly as he wanted to enjoy life not waste it training. He spent time doing all sorts of things: playing with other children (he always won), playing games with his grandparents (he always won), reading and general studying (you can't really win that), and playing with his, quote-unquote, "little sister" Jun (who was actually the daughter of Iori and Aika).
He was pretty sure the varying, impossible relative terminology was an inside joke at this point.
Either way, he still found his progress rather fascinating. Studying how his chakra seemed to ebb and flow was oddly mesmerizing. He didn't know if it was much of a headstart either as, once again, he had no idea what the normal chakra-sensing age was at.
Even after he got to that point, he didn't particularly increase his training. He was still a small child, and they weren't usually given enormous amounts of alone time to begin with. The only reason he could get away with his meditation was because it didn't really look like anything to an observer; that trait wasn't universal.
He decided he would train chakra control next. He couldn't exactly climb trees without people noticing, but what he realized he could do, was try to stick small objects to his hands and feet. It wasn't a perfect replacement for the proper training, but it was the best he could do given his circumstances.
His training time was still rather limited; he had no real alone time so he could only sneak in bits of training here or there when people either weren't in the room or were preoccupied and wouldn't notice the various knickknacks that were sticking to his hands like glue.
With two years until he would be the age to start the Ninja Academy, he believed he would have a fairly solid headstart.
He made sure to enjoy himself as well. Jun was, frankly, adorable, and he enjoyed spending time with his family, who he grew to consider more his family than the one he left.
Not that that was a high bar considering he hated the family he left behind with a burning passion, but still.
More years passed and, finally, his sixth birthday had arrived. He was officially old enough to be placed into the Academy.
The day itself was full of cake and festivities, with Kusuri's grandmother having made said cake.
The day that followed was a touch less magical.
Not long after he woke up that morning, Kusuri found that Iori was at the house. Kusuri was confused as to why he would be there that early and became even more confused when he saw the serious looks on his grandparents' faces.
"Uncle Iori, what's going on?" Kusuri asked inquisitively.
"Well, for starters, you and I are going to do some important ninja things," Iori answered.
Kusuri could tell he wasn't telling the complete truth. The looks on his and Kusuri's grandparent's faces gave that away easily.
"Where are we going?"
"It's a... uh... suprise?"
Since Kusuri couldn't do much about it, he gave up getting a real answer and went back to his room to get changed out of his pajamas.
"I've never met a kid quite like Ku," Iori thought out loud.
"Yes," Toshiyori responded, "He is certainly quite inquisitive. I suppose that explains why he's so observant for his age."
"Were you joking when you said you'd never won a game against him?"
"No. Even the games with no skill components. If not for the fact that he was six, I'd swear he counted cards."
Overhearing this from his room, Ku chuckled a bit, since he actually could, and did, count cards.
While changing, he took a look in his mirror, examining his face a bit.
It had grown familiar to him over the years but some features of his face were still a tad unnerving to his old-world sense of what features humans were supposed to have. Namely his hair and eye color.
His eyes were an odd purple, and his hair was an incredibly dark red. His hair was so dark he, and most others, actually mistook it for black at long distances or in weird lighting.
Shaking his head to reorient himself, he continued getting dressed.
He reentered the living room fully clothed with simple day wear, then walked over to Iori's side.
"You ready bud?" Iori asked.
Kusuri nodded. Iori then nodded as well to Toshi and Ina and left with Kusuri at his left.
--------
"Are you going to tell me where we're going now?" Kusuri asked a few minutes into their stroll.
Iori crouched down a bit.
"Well you see, we're going right about... there!"
Iori vaguely gestured with his right hand before pointing at a large building down the street from them.
Kusuri paled.
It was The Hokage Mansion.
"Ohcrapohcrapohcrapohcrapohcrapohcrap! Did someone see me training?! IS MY INTELLIGENCE TOO SUSPICIOUS?! AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAH!"
Despite his inner turmoil, Kusuri did his best to not look terrified.
It didn't work very well, so he hoped Iori would simply write it off as nerves.
As they approached the building Kusuri came to realize just how large it was. It was rather imposing by itself, even if you ignored the elite ninjas that resided within.
The enormous wooden doors were opened for them as they approached, although they could not see the people who opened them.
Kusuri just kept close to Iori, still trying to make his fear appear a bit more normal.
They walked inside and up some stairs before arriving at the Hokage's office.
The doors seemed to open themselves with a creak, similar to the ones at the front.
It was at this moment that Kusuri saw the first person he knew about from his previous life.
Kusuri was still terrified, even as the inviting old man beckoned them over like an elderly relative.
Hiruzen then gestured for them to sit down.
After they had, he began to speak.
"I assume you are wondering why you've been brought here, correct?"
Kusuri simply nodded wordlessly.
Hiruzen sighed.
"Frankly, this meeting was originally intended to happen when you were older, but the village elders decided it needed to happen sooner rather than later."
Now Kusuri was just confused. It had been preplanned? The elders were involved? Why was he important?!
"Have you ever been told what happened to your parents?" Hiruzen asked.
"No. I never asked. I assumed they would tell me when I was older. Which I guess is now," Kusuri responded with a bit of trepidation.
"Your parents died not long after you were born," Hiruzen began.
Kusuri had guessed that, but that hardly seemed important enough to warrant this.
"They were refugees from Sunagakure"
That was.
"Iori found them, and you, in a small carriage about a kilometer from the border of Konoha. With the three of you, we found a variety of ninja equipment, the most important of which were scrolls. The scrolls are sealed with a special seal from a Suna clan known as the Hinketsu. A clan which both you and your parent are members of by blood."
Kusuri was in shock. He certainly didn't see this coming, but who would've? Not only that, but such a clan's existence was news to him.
"Not only are you a descendant of the clan, but you also possess their kekkei genkai, which we hope will allow you to release the seal."
Kusuri passed out.