In an interview with Detective Conan creator Gosho Aoyama published in Weekly Shonen Jump magazine and Weekly Shonen Sunday (via Twitter), Eiichiro Oda talked about giving Luffy the Gear 5 power-up and how that was something he always wanted to do. “For the concept, think of it as if I suddenly drew ‘Tom and Jerry,'” he said. For the author, what mattered was that he “really want to have fun, and I think that it’s okay if people don’t like it. I just want to play around with my battles.” Indeed, Oda goes on to lament the way manga has shied away from doing “silly expressions that were so characteristic in manga” like “making the character’s legs go in circles when they’re running” — and he isn’t wrong.
Weekly Shonen Jump, where “One Piece” is serialized, has a long tradition of stories unafraid to get goofy with silly cartoonish expressions and imagery like “Dragon Ball” and “JoJo’s Bizarre Adventure.” In recent years, however, the biggest stories in the magazine have been gritty and horror-inspired action series like “Chainsaw Man,” and “Jujutsu Kaisen.”
“Nobody draws them anymore even though they’re our predecessors’ creations who also left many formula we still use,” Oda continued. “I want and have decided to have fun, and I feel like I’m finally able to do that. When I was drawing this, I actually had fun.”
That’s why Gear 5 feels like such a monumental power-up, because the opposite of the traditional idea of a character becoming more serious as they become stronger. Luffy is constantly laughing, bouncing around and changing the reality around him like making the ground rubber and pulling it up to reflect an attack. The way he utterly disrespects and mocks his adversary Kaido during combat — like using him as a jumping rope — is straight out of “Tom and Jerry.”