XAMISI

ahahahaah... yeah I'm still deciding on the costume... I thought about making him a vibranium braided suit, but! I think Peter can't have everything, otherwise he'll end up like the one in the MCU. make your choice which costume you want to see?

high school

yes, but he won't use them frequently

also the main character can have other training of this kind later on, no worries about that

thank you for your opinion ^^ that's why I mentioned Kakashi, actually I think the same as you on this point, but I try to put myself in my character's head, in fact I have a personality profile in one of my documents, and I wanted to stick to it 100% without making any changes along the way, so the main character saw in Gai a way to go beyond his limits by following a training that he would never have done on his own even if he thought he would...

Let's say that from the main character's point of view, he doesn't have to learn anything about Fuinjutsu anymore, he was able to change dimension/universe only with his knowledge and ingenuity and also thanks to the system that provided him with quite a lot of resources, however I also understand your point of view, and I have to say that I thought about it for a long time before writing this. SPOIL but the MC has plans that require a logical brain and the ability to make a person enter a genjutsu with a simple look, so I opted for the Nara clan because they are underused in fanfiction, and the Uchiha for the sharingan which will be very useful for him, and I also thought about the Senju but I think it was too cliché and overused...

Thanks for the info again, I'm going to do more research on this, I must admit it's been a long time since I've seen Naruto...