Monkey D. Luffy, also known as " Straw Hat Luffy" and commonly as "Straw Hat", is the main protagonist of the manga and anime, One Piece. He is the founder and captain of the increasingly infamous and powerful Straw Hat Pirates, as well as one of its top fighters. He is also one of the Four Emperors that rule over the New World. His lifelong dream is to become the Pirate King by finding the legendary treasure left behind by the late Gol D. Roger. He believes that being the Pirate King means having the most freedom in the world.
Luffy has gone up against numerous global powers around him, starting with fighting the most powerful pirates in the East Blue and moving to clashes against the Marines, Seven Warlords of the Sea, Cipher Pol, World Nobles, and even the Four Emperors of the Grand Line, emerging victorious in a majority of these battles. He invaded and indirectly caused the annihilation of Enies Lobby, escaped the impregnable Impel Down, and was a focal figure in the Summit War of Marineford. He has also either defeated or befriended seven of the eleven known past or present Warlords prior to the organization's dissolution. Furthermore, Luffy has invaded the territory of the Four Emperors on multiple occasions, and eventually managed to defeat one. Luffy's accomplishments and heritage have caused him to be labeled as a "Dangerous Future Element" while in the process gaining a reputation for being "reckless" and, in some cases, "insane", earning the wrath of Fleet AdmiralSakazuki, the Marine Headquarters, and even the World Government.
Luffy also has a penchant for attracting followers and has unwillingly been named the leader of the Straw Hat Grand Fleet, consisting of seven pirate crews who swore to come to his aid whenever he wishes. After learning of this and his exploits against the Big Mom Pirates, the press labeled him the "Fifth Emperor of the Sea", though many prominent figures initially considered this to be exaggerated. However, after defeating Kaidou at the end of the Wano Arc, Luffy was officially declared as one of the Four Emperors by the World Government along with Buggy, replacing Kaidou and Big Mom.
Having had a bounty of 300,000,000 before he arrived at the Sabaody Archipelago, Luffy was one of eleven "Super Rookies", pirates who simultaneously reached the Red Line with bounties of over 100,000,000 shortly before the Summit War.  He, the other ten Super Rookies, and Marshall D. Teach would go on to be referred to as the "Worst Generation". Eventually, his conquests and his reputation end up contributing to his current bounty of 3,000,000,000.
Luffy has black shaggy hair, round black eyes, and a slim muscular build. He is renowned for his trademark straw hat (from which he gets his nickname "Straw Hat Luffy"), which was lent to him when he was young by the legendary pirate captain, "Red-Haired" Shanks, who in turn received it from Gol D. Roger. He wears short, blue trousers with cuffs, sandals, and a sleeveless red vest. Luffy also has a scar with two stitches underneath his left eye, which he earned by stabbing a knife under his eye to show Shanks that he was tough and not afraid of pain. He was severely wounded by Akainu in the Summit War of Marineford, leaving a large X-shaped scar on his chest.
Before the Timeskip
Similar to most of his male crewmates, Luffy has the same outfit throughout most of the series (with the exception of Nami and Nico Robin, who frequently change their outfits). Luffy will often wear a different outfit to suit the climate of an island (such as a hooded parka on Drum Island or desert robes in Arabasta) but will switch back to his trademark red vest and blue shorts after the adventures on that island are over. Despite this, he will wear his usual outfit in different colors and has been known to sport other miscellaneous items on his person from time to time like in Thriller Bark and Sabaody Archipelago. According to Eiichiro Oda in 37 Volume SBS, Luffy does not know how to dress stylishly so sometimes he is advised on how to dress by more fashionable team members, Nami, Usopp, Sanji, and Robin.
During the Drum Island Arc, he wore two different parkas, the first being a dark red parka with fur on the cuffs, hood, and hem, and then a checkered, hooded parka with the colors white, orange and bright yellow, which Nami wore in the beginning.
During the Arabasta Arc, he wore desert robes consisting of a dark red robe with three white rings decorated along both sleeves and a light blue wrap over his head.
During the Skypiea Arc, he wore a black wristband around his left wrist with a white bangle over it. In 37 Volume SBS, Oda said that two members of his crew lent him accessories: a black wristband by Usopp and a white bracelet by Sanji.
During the Long Ring Long Land Arc, Luffy wore an afro on his head, dark red shorts, and red bandages on his feet, getting an image of a blue flaming skull and crossbones painted on his chest as well, when he was fighting Foxy.
During the Enies Lobby Arc, he wore black shorts with more pockets than his blue shorts, which he noted he could not fit his meat in.
During the Thriller Bark Arc, he wore an orange vest and red shorts. After the battle against Moria in Thriller Bark, Luffy wore a dark decorated, jeweled armband around his left bicep, given to him by Nami. This armband was later revealed to be a map that leads to Captain John's lost treasure, which Buggy sought for some time; Luffy handed the armband over to Buggy in exchange for his services in navigating through Impel Down.
During the Sabaody Archipelago Arc, in the manga, he wore a blue vest and red shorts (which can also be seen on the cover of volume 52). In the anime, he wore the same blue vest, but dark blue shorts.
During the Impel Down Arc, Luffy wore his outfit from his stay on Amazon Lily until after his fight with Magellan, at which point he replaced his light blue vest with a bright yellow vest given to him by Inazuma.
No matter where he is, Luffy wears his Straw Hat through absolutely everything, though at the start, the hat was prone to get knocked off his head easily, forcing Luffy to either put it aside or have someone hold onto it during fights. From the Arabasta Arc onward, he has gotten a string strap for it, which was sewn on by Nami, allowing the hat to hang from his neck during fights.
During his return to Marineford to give a silent prayer, Luffy was briefly shown with four characters written on his right arm spelling 3D2Y, with the 3D crossed out to symbolize that the Straw Hat Pirates should meet up in 2 years (2Y) rather than the 3 days (3D) as planned after fleeing from Bartholomew Kuma.
After the Timeskip
After those two years, a few things have changed. Luffy wears an open, long-sleeved red cardigan with four buttons (which shows the X-shaped scar covering most of his chest he received by then-AdmiralAkainu), with a yellow sash tied around his waist, somewhat reminiscent of Gol D. Roger's outfit. He has grown slightly taller and is shown to be significantly more muscular due to his training. This can be seen in his slightly thicker neck, more pronounced deltoids, and better-defined chest. During his fight with Sanji, Luffy loses one of his top teeth after being struck by a Diable Jambe Joue Shot directly into his face. However, it grew back after he drank a bottle of milk.
During the Dressrosa Arc, Luffy wore an open, short-sleeved shirt with a sunflower pattern, standard blue shorts, and a yellow sash. He also wore a fake beard. Upon entering the tournament for the Mera Mera no Mi in the Corrida Colosseum, he wore Viking-style armor, complete with a sword and shield until it was stripped from him due to a violation of the weight restriction. Upon revision to meet the weight restriction, he added a cape and wore the same Viking style helmet he wore previously, along with his registration number '0556' and the word "Lucy" written on the back of his shirt, obscured by his cape. When he recovered after his battle against Doflamingo, Luffy wore a red tank top along with his standard shorts in brown (dark grey in the anime).
During the Whole Cake Island Arc, Luffy wore an open, fancy white cardigan with puffy sleeves along with his standard shorts in red. He also had a decorative scarf wrapped around his straw hat after landing at the Seducing Woods, though he appears to have lost it during his battle with Charlotte Cracker. These clothes were eventually torn to shreds after several battles and he later dons a new outfit to meet with Capone Bege; a red suit jacket with a brown shirt and a pink ascot along with red formal shorts. He also fitted a black fedora to the top of his straw hat.
During the Wano Country Arc, Luffy wore a red yukata with patchwork mon of a blue rounded sun on a cyan background and a yellow obi. He also had a topknot on top of his hair. He also had the Nidai Kitetsu he borrowed from Tenguyama Hitetsu. Before beginning the assault on Onigashima, Luffy received a set of samurai armor from Hitetsu. When helping Kin'emon and the others against Kaidou's fleet at sea, Luffy wore a long, dark-colored coat over his usual attire. He also swapped his regular sash and pants for a purple and orange-brown one respectively. He also briefly wore a Beasts Pirates disguise (created by Kin'emon) when infiltrating Onigashima.
In Movie 3, he wears a red shirt with the number "01" in black in the middle. A deer costume with a fur coat and two tree branches for antlers was also momentarily seen.
In the G-8 Arc, he infiltrates the kitchens as a Marine cook, wearing a white cook uniform, a blue scarf on his neck, and a white cook hat covering his straw hat.
↑One Piece Manga —
Chapter 1053 (p. 4-5), Luffy's bounty is doubled and is officially declared an Emperor.
↑One Piece Manga and Anime — Vol. 1Chapter 1 (p. 44-45) and Episode 4, Luffy first reveals his dream to Shanks as the latter leaves Foosha Village with his crew.
↑One Piece Manga and Anime — Vol. 52Chapter 507 (p. 9) and Episode 400, Luffy states his belief that the Pirate King has the most freedom in the world.
↑One Piece Manga and Anime — Vol. 1Chapter 1 (p. 19) and Episode 4, Lucky Roux reveals that the Gomu Gomu no Mi is the fruit that the crew had found and taken from an unspecified enemy before a young Luffy unknowingly ate it.
↑One Piece Manga and Anime — Vol. 50Chapter 486 (p. 5) and Episode 378, Luffy takes an armband from the treasure trove on Thriller Bark, and Nami lets him have it because it does not have any gems on it.