Like many of history's most popular action anime series, One Piece has seen its main character, Monkey D. Luffy, develop significantly in strength through many transformations; however, when ranking them, some stand out more than others. One Piece has seen the Straw Hat crew clash with increasingly powerful foes who have forced Luffy to improve himself and find creative ways to use his unorthodox abilities, culminating in more than five forms.

When Luffy's adventure began on the waters of the East Blue, he'd barely begun to tap into the true potential of what his Devil Fruit was capable of. The fact that his Gum-Gum Fruit was really one of One Piece's strongest Devil Fruits modeled after a legendary figure who'd been worshiped as a sun god, representing freedom for many, completely changed fans' perceptions of the Straw Hat Captain's powers. Each time Luffy found himself outclassed, he made a habit of finding a way to come out on top, and sometimes, it took a new Gear transformation to do so.

7 Fourth Gear: Tank-Man

Debuted in One Piece Manga Chapter #842 & Episode #806 of the Anime

After Fourth Gear's reveal at the end of the Dressrosa arc, fans didn't expect to see another transformation so soon into the following arc. It didn't take long for Luffy to stir up trouble in Whole Cake Island, resulting in a challenging battle against one of the island's strongest commanders, Charlotte Cracker. His ability to create endless tough biscuit soldiers proved too much for Fourth Gear's Bounce-Man, so Luffy had to think with his stomach to come up with a form that has only been used once in the series: Fourth Gear Tank-Man.

By eating enough of Cracker's creations, Luffy's full stomach converted the food into enough energy to create the Fourth Gear Tank-Man form. It made him durable enough to absorb attacks and reflect incoming attacks or enemies with enough force to send them across huge distances. Tank-Man is slow and was specifically helpful for Luffy's predicament with Cracker, but it likely won't be used again because it's been made redundant with Luffy's most recent power-ups.

6 Third Gear

Debuted in One Piece Manga Chapter #403 & Episode #288 of the Anime

Luffy seemed more than prepared to take on almost any challenge with the dramatic upgrades that Second Gear provided, but he still felt the need to come up with another new form in case Second was not going to be enough. By blowing air into his fist and enlarging it significantly, the Straw Hat Captain was able to come up with Third Gear, a larger-than-life ultimate attack. While Gear Three allows Luffy to size up to foes much larger than himself, it's a technique that had a high risk, high reward.

Rob Lucci versus Luffy is regarded as the One Piece by many. It provided a challenge that pushed Luffy further than any opponent so far. When things started to get desperate, Third Gear was used for the first time, and a giant fist crashed through the side of the Marine stronghold. Luffy eventually learned to inflate multiple limbs for several grand-scale attacks. Third Gear once had the unfortunate side effect of temporarily turning Luffy's miniature. He later learned to use it without the blowback and enhanced its destructive output by infusing its attacks with Armament Haki.

5 Base Form Luffy

Debuted in One Piece Manga Chapter #1 & Episode #1 of the Anime

Even though Luffy has evolved his abilities with his Gear transformations, he proved capable of implementing his new powers to make his base form strong enough to handle almost any situation in later arcs. Before One Piece's dramatic time skip, Luffy was significantly outclassed by Marine iral and Pirate Emperor-class opponents. However, that all changed after he was taught to control all three types of Haki from the First Mate of the previous Pirate King.

Silver's Rayleigh was a massive contributor in helping Luffy level up his base form and his rare ability to use all three types of One Piece's mysterious Haki powers. Those abilities also helped improve and create new Gear transformations. Still, they also helped the Straw Hat Captain deal with nearly anyone who tried to pick a fight in his base form. Without transforming, Luffy can use Haki to harden his body with Armament, sense incoming attacks with Observation, and knock out weak willed foes with aura alone with Conquerors Haki, which he's weaponized further during Wano.

4 Fourth Gear: Bounce-Man

Debuted in One Piece Manga Chapter #784 & Episode #726 of the Anime

After training for two years to protect himself and his crew from the dangers of One Piece's roughest seas, the Straw Hat Captain's mix of Haki with Gear 2 and 3 abilities was more than enough to handle the foes waiting on Fish-Men and Punk Hazard islands, but not Dressrosa. Doflamingo had lived up to his intimidating reputation with his Awakened String Devil Fruit powers that forced Luffy to use a new form he had not yet mastered. After years of watching him develop his Gear techniques, excitement nearly reached its peak among the fan base when Fourth Gear first debuted.

By combining his mastery of Armament and Conquerors Haki with his Fruit powers, Luffy developed Fourth Gear, and while he'd later find different alterations of the transformation, Bounce-Man was the first fans saw. The ordinarily thin and stretchy Luffy becomes a hulking torso complete with black Haki-infused markings covering his arms and leaving striking marks on his inflated chest. By manipulating air bursts, Bounce-Man allows Luffy to fly, but he can also compress his limbs into his body to deliver extremely powered-up attacks like the catastrophic King Kong Gun or relentless Kong Organ Gun.

3 Fourth Gear: Snake-Man

Debuted in One Piece Manga Chapter #894 & Episode #870 of the Anime

The Fourth Gear transformation provided the most versatile power-up Luffy had unlocked so far, as demonstrated by its many forms, but its final and arguably coolest was Snake-Man. Unlike Bounce Man, the form is lean, mean, and less focused on delivering impactful damage. Instead, its primary focus is to overwhelm agile foes with a quick salvo of attacks, all infused with Haki capable of providing multiple punches from all directions in seconds.

Luffy's Snake-Man can quickly redirect his attacks by combining his considerable skill with Armament and Observation Haki. Characters like Charlotte Katakuri and Rob Lucci are some of the deadliest and strongest characters in One Piece's world, but even their frightening speeds would have to work hard to avoid all of the attacks Luffy can deliver in his fastest form. While it is fast, Luffy's Snake-Man power can also deliver devastating damage with attacks that increase in speed the longer they chase their target.

2 Second Gear

Debuted in One Piece Manga Chapter #387 & Episode #272 of the Anime

After failing to keep Robin safe and being soundly defeated by the icey iral Kuzan and the 9 leader Rob Lucci, the Straw Hat Captain grew more determined to improve his skills more than ever. The Water 7 arc proved that while Luffy's skills were noteworthy, he'd need to shift his talents to the next level if he was going to be able to protect those he cares about in One Piece's increasingly dangerous waters.

After barely making it to Enies Lobby, one of the Marine's most notorious strongholds, Luffy declared war on the World Government to save Robins's life and also demonstrated a dramatic upgrade in his combat performance with the Second Gear transformation. By accelerating his body, Luffy's speed and power dramatically increased, allowing him to punch so hard he hit foes from a distance with concentrated bursts of air. The upgrade seems to cause his body to heat up as it turns Luffy red, causing steam to follow wherever he goes as he sures his limits.

1 Fifth Gear: Sun God Nika Unleashed

Debuted in One Piece Manga Chapter #1044 & Episode #1071 of the Anime

Luffy's Fifth Gear is his best One Piece form so far, not only because it's the most visually stunning but because it completely recontextualizes the beloved character's abilities. After it was fully revealed that the Gum-Gum Devil Fruit was, in fact, the Human-Human Fruit, Model: Nika, a godlike figure representing freedom, many of Luffy's previous triumphs made a lot more sense. After Luffy awakens his Devil Fruit, he becomes the most free warrior on the battlefield, allowing him to do almost anything his imagination can come up with.

Audience expectations and the internet were broken with Luffy's Fifth Gear debut. Kaido had endured an entire night against over a dozen of One Piece's best fighters, but it wasn't until Luffy unlocked Gear Five that the Pirate Emperor finally met his end. Like other Awakened Fruits, Luffy gains the ability to manipulate his surroundings, transforming his environment into a bouncy landing or even transforming objects into weapons like turning a tree into a nuclear blast deflecting baseball bat. Luffy's used Fifth Gear in several creative ways, and he likely has more to show fans before One Piece ends.

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