in a room of fear gas and itachi has scarecrow in his genjutsu. who would in?
Itachi gets stomped here, lol. IIRC, neither Itachi nor anybody in Naruto has poison resistance feats. The fear gas that Scarecrow uses is a hallucinogenic that makes it impossible to concentrate on anything other than what you fear. Itachi has enough trouble using the Mangekyou Sharingan under normal circumstances because of how tiring it is and how much chakura it uses, adding the fear gas would make it 10x worse. His brain would literally not be able to function normally. Unless someone can show me how Itachi uses Tsukuyomi while he has a hallucinogenic pumping through his Central Nervous System that makes it impossible for him to concentrate, he gets stomped.