Of all the transformations showcased by Monkey D. Luffy in Eiichiro Oda's One Piece, Gear 4 was a sorely needed power-up at the time of its introduction during the Dressrosa Arc. It was the first new form that Luffy demonstrated after the time skip, and played an instrumental part in his eventual defeat of the Warlord Donquixote Doflamingo. Since then, Luffy has gone on to use Gear 4 against the likes of Charlotte Katakuri and the Emperor of the Sea, Kaido, although it did not provide much assistance in the latter fight.