Luffy Haki In Marineford Episode ((install)) -

While the Marineford event was the most famous, it wasn't the first time Luffy used Haki: Reddit·r/OnePiece Luffy used conquerors haki and man wtf (1st watch notes)

He ran.

Luffy ’s use of Haki during the is one of the most iconic moments in One Piece , signaling his transition from a "reckless rookie" to a world-class threat. While he had shown brief, unconscious bursts of power before, the scale and stakes of the display at Marineford changed the trajectory of the series. The Pivotal Episode: Luffy Unleashes Conqueror’s Haki