Joy Boy might not have been a giant, Luffy just needs to catch up.

SUMMARY

A fan theory explains that the original Joy Boy might not have been a giant like the huge straw hat suggests.
He might have been able to transform into a giant at will.
Luffy thus needs to catch up to those powers and develop Gear 5 further.

Joy Boy’s true identity has been a matter of turmoil for One Piece fans. Was he a hero or a villain? A just rebel or a crooked mastermind? Until Eiichiro Oda comes clear with the original user of the Hito Hito no Mi, things will remain unverified.

However, this has not stopped fans from speculating about Joy Boy. The enigmatic rebel could have been a giant or belonged to a different race that ceased to exist. A fan theory tries to figure out the connection between Joy Boy and Luffy.

Spoiler Alert!
One Piece spoilers ahead

One Piece Theory Debunks if Joy Boy was a Giant

Joyboy's Straw hatJoyboy’s straw hat | Viz Media

Joy Boy is often considered to have been a giant. This opinion is solidified by the presence of the giant strawhat at Mary Geoise. Even the Iron Robot is a giant mechanism who wakes up at the sound of the Drums of Liberation. Zunesha was also a comrade of the Nika user. Thus fans were of the opinion that Joy Boy was a giant like the Elbaf inhabitants.

But a new theory choose to debunk this opinion by simply stating that Joy Boy’s control over his Devil Fruit is what led to him being perceived as a giant. You have seen Luffy being able to change the size of a specific body part or himself as a whole. If he had more control on Gear 5, he might even be able to maintain his giant form for longer.

the iron giant apologizing to joyboyThe Iron Giant apologizing to Joyboy (Credit: Viz Media)

What if Joy Boy simply knows how to use this power to his advantage? The giant straw hat could exist simply because the last Joy Boy could not only manipulate his own size but also that of the things around him. Luffy might not have achieved the power to do the same yet. If the last Joy Boy died in his giant form then the existence of the giant straw hat would make sense, and explain why it didn’t shrink for all these years.

The Possibilities for Luffy to Improve His Gear 5 Form

Gear 5 Luffy in One PieceGear 5 Luffy in One Piece

If Joy Boy could indeed access and master greater power, it means that Luffy is bound to stumble upon them soon. In fact, you might even receive a Gear 6 form in which Luffy would be able to maintain giant form for an extended period of time or till as long as he needs. Hopefuly, he will be strong enough to not shrink to a child, once he exhausts himself in the new form.

The theory of a second awakening of Luffy could be true, and Luffy is yet to master a more superior form. Given that he has to face enemies that are stronger than him quite a few times over, the pirate will desperately need a new power-up.

In his current giant forms, Luffy tries to keep his straw hat the same size as before, probably for nostalgic reasons or not to damage it. Joy Boy might have not had the same philosophy, so he might have resized it according to his forms.