Monkey D. Luffy/Misc., One Piece Wiki

When drawing One Piece, Eiichiro Oda was heavily influenced by the manga Dragon Ball, and had the series in mind when designing his characters. Oda has said that when he was creating Luffy, he was thinking about "manliness", because Dragon Ball had already done all the things that a child could possibly be happy about. Luffy was first featured as the main protagonist in the first pilot of One Piece Romance Dawn V.1 in the Shonen Jump specials showcasting upcoming artists, about a year and a half

Monkey D. Luffy - Wiki

Monkey D. Luffy - Wiki

Monkey D. Luffy/Misc., One Piece Wiki

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Who is Monkey D. Luffy in One Piece?

Monkey D. Luffy - Wiki

Does Luffy really have Toon Force, or are people just being biased? - Quora

Monkey D. Luffy/Misc., One Piece Wiki

Monkey D. Luffy/Misc., One Piece Wiki