I have no idea how exactly to make my HC into fic canon, so imma plop it here so the brain worms stop eating me:
Taking into consideration that the Infinite Tsukiyomi is a dream world, and Itachi’s Tsukiyomi is called the Nightmare World, I think it is reasonable to assume that they both work basically the same way, I.e. reflecting the subconscious of whomever they’re cast upon.
(This is reinforced for me I suppose by the old fandom theories about how Itachi’s Tsukiyomi worked, and I’ll own that bias lol.)
Anyway, something that came up way back then was an idea I liked, which is that Itachi’s Tsukiyomi works by blending the user’s influence (because Itachi can, sort of, manipulate the content consciously) and the victims deepest (subconscious or unconscious) fears or desires.
How much of each takes precedence I think is something Itachi can control — unless their fear/desire is so overwhelming that he can’t actually impress anything upon it, or if they lack the notion of either entirely.
Anyway, point is, this makes his scene with Kakashi in pt 1 very interesting. 🧐
As we know Itachi crucified him and stabbed him relentlessly in deliberately non-lethal spots for 3 full days.
Except…I’m not actually convinced, from a watsonian perspective, that Itachi was the one making up this hellscape, not on his own.
The following is entirely speculative, so to each their own opinion, but it suits my little fic-bearing heart just fine to presume that:
1. Itachi was trying to go easy on him. His objective was to capture Kakashi alive (…to what end we can only guess; I’ll write an alternate fic for that scenario someday :0) and he clearly holds Kakashi in high esteem, not even mentioning the whole former colleague thing. It’s very possible that Itachi’s actual objective, had he managed to successfully capture Kakashi, was to share intel rather than collect it, and to that end he needed to ensure that he disarmed his senpai without killing OR severely traumatizing him, because he did need Kakashi to have some hope of trusting him if that plan was to succeed.
2. However, Itachi was still figuring out the details of how his power worked; he knew it’d make him go blind eventually, so he tried to minimise how often he used it, at the expense of taking forever and a day to work out the kinks. One of which is the likelihood that, particularly in the absence of other conscious influences from him, the other persons fears/desires would manifest more vividly.
Thus we get a crucified Kakashi…because of how his father died.
Now, from a doylist perspective, obviously, the entire thing is just about the aesthetic aspect of Scarecrow vs Crow.
But the watsonian believer in me says that being crucified literally like that is a reflection of a deep, somewhat neglected fear by Kakashi of becoming just like his dad. After all, he spent so much of his young life trying so hard to be the opposite of him, all rules and no play, until Obito convinced him otherwise.
But trauma like that doesn’t just vanish. Kakashi might be very mature about it, or we can presume so, but the fear never fully left him — he’s just more aware of it and capable of acknowledging it without letting it totally consume him like he did when he was tiny.
Which contributes probably to the utter lack of long term consequences for that Tsukiyomi nightmare; first, physical torture is the easiest to psychologically resist, and second, he was at least subconsciously already aware of that fear, so while seeing it manifested certainly had an effect, it wasn’t enough to really re-traumatize him or anything.
What’s more interesting to me, in the name of catharsis, is how Itachi interpreted all that.
Sadly we don’t get to see that, but I reckon it did answer a few questions he might’ve had and probably gave him a greater sense of grace or respect towards Kakashi; or at least that’s what we are working with for A Fawn in the Grass purposes lol.
Ah the fic bunnies will surely nuzzle me to death about this concept until I actually write something down, but I am determined to finish one fic at a time right now. Otherwise I just spam 6 at a time and none of them ever get done lol.
But I will come back to it some day. Because so much could have changed if Itachi had actually captured Kakashi on that day.
I leave you with that while I go contemplate alternate timelines 🤣