Well for a regular genjutsu he's already able to break out of it, So with high level genjutsu he'd be able to break it out much easier but for genjutsu like Itachi's Tsukuyomi were it only needs one second to hit so most likely the impact of the damage would be much less. I'm not sure if the Demonic Illusion: Toad Confrontation Chant can be broken out of when the toads continue to sing but , it does give gai a much better shot.
For tsukuyomi I think its the same deal. While in the real world its only seconds, in their realty its however much time Itachi wants so I think he has time to open gates, which hes a master at so the can just be opened. I see as just like Izangi where the actual reality doesnt matter.
However since Ma and Pa's song completely paralyzes the body, idk what he'd do then lol. Might Guy might be toast lol.
Seems very logical but what made u come up with this theory in the first place my dear Melizzle

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Hmm I was thinking about Guy, theres kinda been a lot of threads about him and I just wondered about him v Kakashi or any other Gen user. I think people only like to think about him as far as hitting and kicking go and not practicality. I'll slap Kakashi if he ever says he's lost respect for Guy again!
Its also dangerous since you dont really know what your doing i.e. blowing up yourself with your own c4! The genjutsu is disrupting your reality so in the one minute your trying to open more gates you could be burning your life energy! And die..... :flaw:
lol yes Diedara was pretty hot headed huh? But The gates are within Guy and not an attack so I think he'll be cool lol.