So far, Luffy has created three Gears with the help of training. These are: Gear 2nd Gear 3rd Gear 4th All three Gears make Luffy extremely formidable, but they aren't nearly as strong as Gear 5th.

Luffy might have thrown Kizaru far away from the battlefield, but he isn't strong enough to kill him yet in One Piece, not ...

The Uchiha's Perfect Susanoo and regenerative abilities along with his physical and chakra-based techniques would probably surpass Luffy's defenses even after Madara activates Gear Fourth or Fifth.