Luffy was born with the power of Supreme King Haki. He awakened this power slightly before the timeskip, and then gained control over it after his training with Rayleigh. Luffy then manifested ...
Oda drops a hint about his end goals in One Piece. With further training and fighting, Luffy's usage of Supreme King Haki will improve as well, which means that he will learn further applications ...
The training that Luffy and Zoro underwent ... to personally instruct the young pirate in the principles of Haki. Rayleigh took Luffy to Rusukaina, a harsh island filled with dangerous animals ...
During his training, Luffy encountered beasts (similar to what he encountered on Elbaph) and learned to control his Haki by going through extreme measures. This trained him enough such that he ...