Throughout One Piece, Monkey D. Luffy has made countless friends and allies, some temporary and some lasting. In fact, One Piece is so crowded that only the most dedicated of fans could name every single person Luffy has ever helped. But Luffy's first friends are iconic, and most of them remain essential to his development and One Piece's overarching story.
Source：https://www.cbr.com/one-piece-luffy-first-friends-chronological-order/
