Naruto Uzumaki hadn't quite figured out what was happening in the classroom. When he saw Iruka-sensei storming out in a hurry, he simply assumed class was over.
"Hey, what's everyone standing around for?! Iruka-sensei already left! Time to crank it up and BRING THE HEAT!!"
With a yell, Naruto leapt up onto a desk, full of energy.
Uchiha Sasuke didn't lower his guard. He still gripped a kunai tightly, eyes alert.
"Idiot."
Haruno Sakura stormed over, fuming. Naruto's heart raced with joy when he saw her approaching.
"Sakuraaaa!"
BAM!!
Sakura leapt up and smashed a fist down on Naruto's head.
"Uzumaki Naruto! Shut up already! Ito Hiromi just disappeared!!"
"Ow—what the heck, Sakura?! That hurt!"
"Wait, wait, wait. What did you just say? Disappeared? Who did?!"
Naruto went dead quiet and turned toward Hiromi's desk.
"Hiromi's gone!" Sakura barked. "So sit your butt down! Iruka-sensei went to find the Hokage!"
"No way... How could he disappear like that?! What happened?!"
Naruto stared at the empty seat in disbelief. Ito Hiromi was one of his few real friends. He'd never judged Naruto for being a Jinchūriki, and he'd even shared food with him. How could he just vanish?
Moments later, Third Hokage Sarutobi Hiruzen arrived at the classroom with Iruka. His face was grim.
Iruka had already explained the situation, and Hiruzen had a hunch.
"Did anyone see exactly what happened?"
Yamanaka Ino hesitantly raised her hand.
"Hokage-sama... I did. Iruka-sensei was explaining the hand seals for the Summoning Technique... and Hiromi started forming the seals. Then—poof—he just vanished!"
Hiruzen and Iruka exchanged a knowing look.
"...Reverse Summoning," they said in unison.
"Iruka," the Hokage said, "Notify Jounin Ito Aoyama. He's the boy's father and head of the Ito clan. There is no known way to reverse a Reverse Summoning. We don't even know where the child was summoned to... or if he can return."
Iruka nodded solemnly. "Understood, Hokage-sama."
After he left, Hiruzen lit his pipe and took a deep puff, staring at Hiromi's empty seat. It reminded him of his old student... Jiraiya.
Jiraiya had once been Reverse Summoned to Mount Myōboku by accident and gained Sage Mode. Could Ito Hiromi have encountered something similar?
Meanwhile, Hiromi himself was stunned.
He had only been casually trying out the seals for the Summoning Technique... and ended up in a strange, foggy dimension. No sun, no light—just endless darkness and a chilling aura in the air.
"What the hell is this place?! Reverse Summoning?
Is this one of the holy lands? But there are no toads... no slugs... no snakes! Nothing!!
How am I supposed to get back?!"
**[Host detected. System binding initiated.]
[Location: Konohagakure.]
[Binding host to Konohagakure Spirits... Success.]
"Wait—SYSTEM?!"
"System, what the hell is going on?! Why did you suddenly bind to me?! Where even am I?! And what do you mean by 'binding Konoha spirits'?!"
**[Host was never meant to exist.]
[In the original causal timeline, host was supposed to die in the womb and pass into the Spirit Realm.]
[System encountered unknown errors detecting host. Had to forcibly breach dimensional barriers and fuse with the Spirit Realm to establish connection.]
Hiromi's jaw dropped.
So that's why he never appeared in the original Naruto story—he was never meant to be born. His reincarnation had altered fate.
The system had come looking for his soul in the afterlife... but he had survived, so it had broken into the Spirit Realm to reach him.
"System... so what kind of system are you supposed to be?"
**[Originally: Many Children, Great Fortune System.]
[However, due to energy loss during Spirit Realm fusion, the original functions have been lost.]
[System has now mutated. Current version: Summoning System.]
[Host may summon spirits as summon beasts.]
[White Tier: Genin-level spirits.]
[Green Tier: Chuunin-level spirits.]
[Blue Tier: Jounin-level spirits.]
[Purple Tier: Elite Jounin-level spirits.]
[Gold Tier: Kage-level spirits.]
"...Many Children, Great Fortune?" Hiromi muttered. "That's actually kind of cool. Shame it's broken."
But this new system... summoning the spirits of fallen shinobi?
"System, wait—does that mean I'm in the Spirit Realm right now?!"
**[Correct. While practicing Summoning, system Reverse Summoned host into the Spirit Realm.]
[Host has now been bound to the Konoha section of the Spirit Realm.]
"But you just said the whole Spirit Realm was fused with me. Which is it?"
**[Host is currently recognized as a Konoha villager. Thus, only spirits affiliated with Konohagakure may be summoned.]
[Only when host dominates the ninja world will the entire Spirit Realm be accessible.]
"Got it... Alright then, System, show me everything you can do!"
**[System Mode: Summoning System Activated.]
[You may now summon the spirits of dead shinobi as your summon beasts.]