Hito Hito no Mi, Model: Nika belonging to the mythical Zoan type is one of the most incredible devil fruits that exist in the world One Piece . This fruit has been Luffy eaten 12 years ago before starting the journey, at that time it had a different name: Gomu Gomu no M i.
True name and true power of Nika was only recently revealed. Left Nika called Gomu Gomu no Mi to hide its true nature and the World Government wants to erase it from history.

Luffy awakens Gear 5 gaining the power of the Sun God Nika.
Left Nika has an amazing ability after being awakened. In the war of Luffy against Kaido The power of Nika the sun god was clearly revealed for the first time, leaving fans extremely surprised.
On the surface, this devil fruit only gives the user a flexible body. When Luffy eat fruit Gomu , his body forever turned into rubber. He can stretch and tighten his body at will, becoming invulnerable to any direct damage, except sharp attacks.
But when the power of Nika It was revealed that turning the user’s body into rubber is just one aspect of this devil fruit’s power. Its true power is to give the user freedom and laughter, allowing Luffy Spread it to everyone around.
Left Nika allow Luffy have incredible freedom to do whatever he wants in battle. From stretching and tightening at will, to even transmitting your power to your surroundings and enemies. This is really what makes it so Luffy becomes very dangerous, especially considering how the mind works Luffy.

Luffy in Gear 5 state is free to do whatever he wants
As powerful as it is, there are still some limitations to the fruit’s power Nika has been suggested in One Piece :
Basically, the only limitation of Luffy about his abilities is his own imagination. This has been seen many times in the battles of Luffy in Wano and Egghead.
For example, Luffy imagined that he could run in the air by moving his legs very fast and he did it. He imagined he could grab lightning and turn it into rubber, and succeeded. Good Luffy imagined that he could turn cartoonishly gray when hit by Boro Breath, and that’s exactly what happened.
Well for anything Luffy Anything you can imagine can make it come true, so your imagination Luffy No matter how big you are, your strength will be as rich as possible. Luffy cannot give life to things he cannot imagine, and his mind is very simple so he only imagines simple things. In fact, Luffy Can be countered in combat. This implies that the power of Luffy can also be counterproductive.
Imagination is certainly not the only limitation of this devil fruit. Luffy also suffers from standard devil fruit weaknesses such as being unable to swim, being countered by sea rocks and bubble guns due to Dr. Vegapunk create. The sea mother still has a grudge against Luffy even though you are a Liberation warrior.

Using Gear 5 causes Luffy to consume a lot of energy.
One more special restriction Luffy emphasized many times. That Gear 5 consumes a lot of power. This means Luffy it is impossible to maintain constant Gear 5 status without endangering one’s own health.
When confronted Kaido, Luffy exclaimed that the form was too laborious and had to be reactivated after it stopped working. In Egghead, fans saw Luffy turned into an old man after the power of Nika disabled. Every times Luffy Use Gear 5, it will put pressure on your body.