I don't own solo leveling or Naruto.
"You don't ever have to forgive me."
...
"No matter what I will always love you."
...
Those were the last words he would ever say to his precious little brother, Sasuke. After releasing the Edo Tensei Jutsu of Kabuto he fulfilled his end of the promise he made to Naruto and hoped he listened to what Itachi said about being Hokage. He disclosed the whole truth to Sasuke about the Uchiha Massacre and expressed his regret for not trusting his little brother from the beginning. He felt at peace knowing he got to say things he wanted to say to Sasuke for all those years he tormented, but never could. His spirit ascended to the heavens with no regrets and happiness knowing a failure like him could protect the Leaf once again even if nobody knew it.
After the events with Sasuke he spent sometime wondering in the pure white expanse of the Pure Lands or, what Itachi thought were the Pure Lands after all a cynical part of Itachi thought it was too good to be true for him to have life in Pure Lands after every terrible thing he did. Even if it was for the sake of everyone in Hidden Leaf Village.
"I've been wondering for some time now, is this infinite void of space my hell?" said Itachi aloud. He would continue wondering like this for several hours, days or months, maybe even years it was hard to distinguish time in a void like this. Until all of a sudden he felt his movements become restricted.
'What! What is happening to me!?' he thought alarmed.
It felt as if he had been restricted by some form of binding like wire or rope keeping his arms pressed against his body.
Normally Itachi would not be caught off guard like this, but due to white void all around him and the the fact that he is a spirit and dead he didn't think he would be attacked.
...
Saiseikai Central Hospital, Tokyo, Japan
...
A boy who looks no older than 15 years of age with lines on face not unlike a certain Uchiha. He was asleep but not a normal kind of sleep, it was a sleep caused by not being able to handle exposure to mana. This was called eternal slumber and this boy has been suffering from it for 2 years now.
After 2 years asleep this boy suddenly woke up and gasping for air.
'Where am I?' he thought.
...
A nurse entering the hospital room to do routine checks on the etrenal slumber patients and the equipment gasped in shocked. He leaned his head out the with his hands on the frame of the door for his balance and exclaimed "We have a code 15 at room 230. Someone get Doctor Takeshi!"
...
'Am I in a hospital?' thought the boy. The beeping monitors, smell of anaesthetic and IV drip in his vein pumping fluids into his body was a big give away to his location. 'Calm down, Itachi. Analyze your surroundings and your current state then act accordingly.' reprimanded Itachi in his head. He confirmed that he was in a hospital room with 6 other patients in the room with the window on his left 2m away, 'Good' he thought. However after analyzing himself he came to the conclusion that he would not make use of the window as an escape route, because of how fatigued he felt at the moment.
...
"Hey kid don't move so much! You've been asleep for a while now just lie down until Doctor Takeshi gets here." said the stranger in concern. Itachi just stared at him with narrowed suspicious eyes, but complied with the man's request and lied back down staring at the white ceiling . He was really starting to hate the colour white.
...
After 2 minutes a man bald middle aged in a white coat with a nametag displaying 'Dr. Takeshi' on it identified that this was whom the stranger was talking about.
"Hello there son, how are you feeling?" asked Dr. Takeshi. Itachi tried talking but immediately widened his eyes and started coughing. "I imagine it would be difficult to speak after not using your voice for nearly 2 years." said Dr. Takeshi matter of factly.
"Here some water, drink slowly." instructed the stranger.
Itachi did as told and after a few moments spoke in a deadly tone, "Explain where I am and why I'm here."