The conversation between human and AI assistant.
In what One Piece episodes does Luffy use Gear Second and Gear Third?
Interesting. How does Gear Fourth differ from Gear Second and Third?
Gear Fourth is a combination of both Gear Second and Third, but with the added strength and speed boost from using Haki. It also changes Luffy's physical appearance, with more muscular arms and legs, as well as a different hairstyle.