in Ino's Swap!verse, she'd be really confused about the lack of Shikako though. She'd think it was a genjutsu, some sort of trap. She could understand someone trying to trap her in her own mind, and perhaps attribute her awareness of it being a genjutsu to her clan techniques. (At least, before she realised it was something bigger) But she wouldn't understand why it was Shikako that was missing, that didn't exist. Out of all the people that might disappear, it was her? It'd be confusing for her, and when she gets back to the DOS!verse, she might not exactly be suspicious but she would definitely be curious.
Ah, but then she'd find out that in this world without Shikako, her mind is perfectly intact. That Shikamaru still has his arm and Chouji's smiles are that much wider.
She'll see all the bad things too, the things that are missing in this world, and she'd feel this nauseous mix of longing and guilt.
Maybe I should write a lil fic about this. BUT I came here to write about Itachi so let's get back on track.
Itachi Uchiha woke up in a small room, his eyes just barely cracked open. There were two packs on opposite sides of the room, propped up against walls of flimsy wood. Light streamed through a high window too small to climb through.
This was not where he fell asleep.
He was not restrained. All his weapons were accounted for, though there were two more kunai in his left sleeve than yesterday and one less in the right. He felt no grogginess or pain other than the chronic ache of illness. He could not detect any traps or malicious intent.
The faint sound of leaves being crushed underfoot told him he was running out of time.
Itachi's eyes swept the room. There were no traps or seals on any surface or object, obvious or otherwise. There was the possibility of seals having been placed on his skin, clothes, or the blanket which he lay on. He palmed two kunai, his hands hidden by his cloaks long sleeves. Any seals may be activated by chakra use; taijutsu was optimal.
He flung himself from the bed, flipping over to land near a corner of the room. Crouched and ready, he faced the bedroll and the door. No traps had been sprung. The footsteps drew closer. They were soft; silent to anyone but himself. That gait... Sounded something like-
The door swung open with a careless push.
"Itachi, what are you? Some kind of jumpy genin" Kisame said.
His words were flippant, but Kisame's (or this imposter's) hand hovered over Samehada's handle. It looked like Kisame in every way. From the scales, the stance; even the misalignment in the scales just above his collarbone
This was no genjutsu, Itachi would not fall prey to such a thing. Nor could any henge fool him.
Itachi did not understand the situation.
After a moment, he spoke. "Did you move me,"
It would have been impossible for Kisame to have done so without him waking up, but perhaps he could fish for information.
"Move you? No, I did not" Kisame said easily, his hand coming down to rest lazily upon Samehada's handle.
He slowly straightened up, tucking his kunai back into his sleeves with practices movement.
"My apologies" He had said calmly, giving a shallow nod. "I was asleep. It seems I am still disoriented."
He decided to play along.
Itachi learned many things in the next few weeks. There were new scars along his body, and old ones seemed to have disappeared. Zabuza of the Seven Swordsman was dead, along with his apprentice. Killed months ago in the land of waves by Hatake Kakashi and Team 7. Naruto Uzumaki was still a genin. Mist had nothing resembling a treaty with Konoha nor Sand.
Sasuke had been hit by the Tsukiyomi.
His little brother had betrayed Konoha for Orochimaru.
His hands curled into fists, drawing the eyes of Kisame. The swordsman had kept a close eye on him, as was to be expected. Especially after his less than impressive reaction to Kisame blithely remarking on Sasuke's… Defection, a week into the genjutsu.
The situation was perplexing. A genjutsu seemed the most logical explanation. If he was caught within one, the caster's skill was unparalleled. It was near indistinguishable from reality, and he seemed to have been caught for an extended period of time. Multiple 'kai's' and self-inflicted wounds had not made the illusion even flicker.
However, the illusion itself made no sense. It seemed as though this world was an exact mirror of reality, minus one factor.
Shikako Nara did not exist.
This is what he could not understand. It was not that she had failed to take the blow for Sasuke, it was that she simply didn't exist that perplexed him. There was no point to this. There was no reason for him to be trapped in a genjutsu where the girl did not exist.
His ravens were near exhausted from how often he'd sent them out to gather and confirm these bits of information. Yet it seemed to be true. There had never been a twin to the Nara heir and as such, she had never been the teammate of his little brother or the Nine tails host, Naruto Uzumaki.
It was a girl with a bright shock of pink hair, a colour he vaguely remembered from the times he had picked Sasuke up from the academy. Apparently, the girl had excellent chakra control, had exceptional intellect and had recently been apprenticed to Tsunade. She had little to no combat abilities and seemed to have shown no outstanding traits of leadership or strategy on any of her missions with his brother, a rather sharp contrast to the... explosive Shikako Nara.
Perhaps this was why he was in this genjutsu.
In this world, the Haruno girl was Sasuke's teammate and in this world, he was in Orochimaru's clutches.
In this world, there was no Nara girl to take his brother's place. His brother had had no protection against his eyes.
In this world, there had been no Shikako Nara to disrupt his plans and in this world, Sasuke had betrayed Konoha for Orochimaru.
It was the massacre all over again. He made the choices he thought were best, and they weren't.
It is very…. Hard to think that you are right when you are smothering a baby. It's limbs waving clumsily and the poor thing's wails growing weaker and weaker. When you've just murdered your own parent's and then your adoring little brother runs in.
His Sharingan had burned them into his mind in crystal clarity. In a way he was grateful.
Even now, he could see those moments dance just under the surface of his eyes. He had made the best choice he could; even if now he spent every moment thinking of better ones.
It had never occurred to Itachi Uchiha that these were not choices thirteen year olds should be saddled with. That thirteen year olds should not be ordered to face the consequences of these actions for the rest of his life. That a thirteen year old simply could not make the best decision in this situation.
All he saw now was another failure. One that he could blame on no one on himself.
He bitterly hoped that this was merely a genjutsu.
Okay so this is kinda a thing. If I continued I think Itachi might go after Sasuke. Maybe just to observe? I'm not sure if he'd be willing to take any action right now, because the choices he makes always seem to go so horribly. Maybe he runs into Naruto?? I dunno, I think he's just a confused, conflicted and indecisive person for a while.
He's like seventeen. He was thirteen when the massacre happened and even younger in the lead up to it. I think yeah, bad decision making runs in the family, but I also think the massacre was largely Itachi trusting that Hiruzen and Danzo, adults that are in charge of the whole village, that he has been taught from a young age to trust and serve, would make the right decisions. Unfortunately, these decisions included the slaughter of hundreds of people and many many children.
He might focus on getting out of the 'genjutsu'. He probably gets back to the DOS!verse with handwavey Sharingan powers that are basically canon.
I don't see Ino agreeing to work with Itachi. Even if he told her everything (which he wouldn't, cuz this is Itachi), she'd still think he was a a shitty and dangerous person that she couldn't trust. Sooooo, Itachi probably observes her. Acts as an anonymous source of info and support? He's good enough to leave her messages without getting caught.
Wait, that's cool but also dumb.
All Itachi has to do is pretend to be someone else.
Basically, the idea I had for Ino!swap was that she travelled through her own chakra while training with her father. Separating herself from Orochimaru in her mind and body every day. Except this time, she had gotten to the source of the problem. Her soul. It's a lil headcanon of mine that chakra is the link between the soul and the body in the naruto verse, and that little bit of the soul are spread across your chakra (because remember when Minato sacrificed himself to the shinigami? his chakra was leaving his body and reforming to look like him). So what happens is that Ino travels through her mind and chakra and finds her soul while fighting Orochimaru's fragment. But then her mind gets caught in it, and then gets swapped for canon!ino. I think I read on one of the forums a theory that the soul is a constant that stretches across the multiverse. This draws on that.
So Itachi pretends to be someone else stuck in that genjutsu with her, and they work together to get out. Ino draws them both towards their souls and Itachi uses his Sharingan to pinpoint them to the right universe? No, no. Ino could do that herself, she's a sensor AND the mind is kinda her clans thing. She can do that herself.
Itachi gives her a power boost so she can take both of them to the right world. And then he helps her out with the Orochimaru fragment. He doesn't destroy it, I don't think it can be. but he does help her weaken and contain it. Then they go on their merry ways. Hmmm, and let's go with handwavey Sharingan powers and genjutsu Tsukuyomi shenanigans for why ino doesn't realise that its Itachi until they are just about to get home. If ino did find out it was Itachi it would be by mistake on Itachi's part. I don't think he'd let someone who interacts with Sasuke so often know he was kinda decent.
So I think Ino might never find out it was Itachi, but she will figure out that he was lying about who he was.