Monkey D. Luffy is the protagonist of Eiichiro Oda's One Piece. With the goal of becoming the Pirate King that was given to him by Shanks, Luffy sets out to sea at the age of 17 to acquire a strong crew and claim the One Piece. Over the years, he has become extremely powerful and is quite possibly the closest pirate to the One Piece itself right now. Expectedly, Luffy's journey to the spot has not been easy.
To overcome the many obstacles in his path, he has had to gain tremendous power and, just like most fictional characters in anime and manga, Luffy has received a number of power-ups over the years. His latest power-up, Gear 5, was used by him to defeat one of the Yonko of the Sea, Kaido. In doing so, Luffy freed the people of Wano and ended up rising to the position of Yonko himself.
The Basis For Luffy's Power-Ups
Characters in fiction are driven by different things, which end up becoming their source of power. For some, this is an unrelenting determination to be the best, such as Zoro in One Piece. Nearly every character in One Piece has their own driving force which makes them stronger. While some power up from rage, others do so through some other means. Luffy's case is quite curious. Ever since the very beginning of the series, Luffy has always powered up in unique ways to best counter the difficult situations that he has been in. This ties very well to his character as Luffy has never gotten stronger through the cliche power-ups such as rage or visceral anger.
Luffy is the personification of freedom and creativity, and as such, his power-ups have always been tied to these two aspects of his character, which is simply beautiful character writing. This was apparent from his very childhood, when Ace and Sabo mocked him for having a Devil Fruit that actually holds him back instead of aiding him. However, over the years, Luffy has used it in such a manner that he has become one of the Emperors of the Sea.
His Gears
Luffy's gears are his biggest source of power. In times of need, he has tapped into his limitless creativity and developed gears to counter the situation that he was in. Instead of the cliche rage moments, Luffy always makes use of his incredible mind in combat and comes up with the most amazing power-ups. During the Enies Lobby arc, he managed to create Gear Second by pumping blood faster in his body. Realizing that his body was made from rubber and capable of sustaining high blood pressure, Luffy was able to attain the same powers as the CP9 merely by using his creative mind.
He created Gear Third in an attempt to increase his attacking power and realizing that pumping air into his bones would give him the body of a giant allowed him to do so. He learned to incorporate Haki with his fruit by creatively pumping air into his muscles and created Gear Fourth. To combat Cracker, he created Tankman, and to overcome Katakuri's Future Sight, he created the faster Snakeman. Luffy's power-ups have always been driven by creativity and freedom which is exactly why Gear 5 is the culmination of everything that Luffy's character is all about.
Why Gear 5 Is Luffy's Best Power
In still losing his fight to Kaido and the latter being declared as the winner of the battle on the rooftop, Luffy's Devil Fruit finally awakened. Previously, it was revealed to the fans that his Devil Fruit is actually a special fruit that the World Government tried to attain 12 years ago. After losing it to Shanks, they changed the name of the fruit in order to hide its true identity. After all, its true powers could only be revealed once it awakened. However, thanks to Luffy's incredible creativity, this fruit ended up awakening and granted him the power of Gear 5. Essentially, Gear 5 is Luffy and his very best since in this form, he becomes the Warrior of Liberation. He fights with incredible freedom and unmatched creativity which even Kaido could do nothing but look at in awe.
Gear 5 makes Luffy much tougher and stronger, however, its biggest asset is that it makes him fight with even more creativity and freedom. These two traits are what define Luffy's character. Instead of being a power-up that is driven by rage or any negative emotion, Gear 5 makes the best use of Luffy's personality and turns it into his biggest strength, making it his most iconic power so far.