One Piece is currently in the Elbaf arc, and it is here that Oda is finally setting up a big confrontation between Luffy and Imu. One Piece fans have been waiting for this battle for years now ...

Gaban, Roger's former right-hand, may train Luffy. Luffy needs stronger Haki for the final war. Gaban could teach Luffy to combine all three Haki types. He might also share crucial lore about Roger.

Luffy's Conqueror's Haki is his strongest weapon, and it played a crucial role in his victory over Kaido. Needless to say, Luffy is the best at using Haki among the Straw Hat Pirates.