Gomu Gomu no Jet Gatling Monkey D Luffy

Gomu Gomu no Jet Gatling (ゴムゴムのＪＥＴ銃乱打（ガトリング） Gomu Gomu no Jetto Gatoringu, literally meaning "Rubber Rubber Jet Gatling")  is used when fighting.

Gomu Gomu no Jet Gatling 

This is one of Luffy's strongest techniques. Luffy stands still, bends forward and moves his arms upwards at speeds which they can no longer be seen, leaving only jet streams in their place, very much like how the Jet Pistol looks.

Personality Monkey D Luffy One Piece

Personality Monkey D Luffy One Piece

Luffy's two dominant traits are his apparent lack of intelligence and his utter fearlessness. Luffy can easily be amazed by the simplest things, such as hermit crabs, and can be confused by concepts such as that by digging a hole right next to another he may be unintentionally filling the other hole. He likes monsters and will ask weird creatures to join his crew (as seen in the Thriller Bark arc, asking a talking tree to join his crew). He also has no knowledge of medicine, when Nami had a high fever he told her to eat cold food and later tried to make Roronoa Zoro better (after battling Bartholomew Kuma) by pouring sake onto him because Zoro likes sake. When attempting to think up a plan to get off of Amazon Lily, while he managed to make some logical sense of where to look, he is seen to strain himself and notes that he is going to feel sick from too much thinking.

His simple mind actually saved him against Hancock's powers because he mistook it for a "Noro Noro Beam", used by Foxy, which brought out a fear of being slowed down (though it is shown later he is simply immune to her powers, because of his pure heart). If Luffy finds something he does not understand, even if someone explained in detail, he calls it a "mystery thing"; like calling dance powder a "mystery powder". One of Luffy's running gags is asking "non-humans" such as Keimi and Brook if they can poop, in which case the answer is usually a yes. Another running gag is Luffy's slow reaction time, especially to freezing temperatures.

The same cannot be said when he is on the field of battle, though; he has been known to dodge bullets with ease. It has been stated more than once that Luffy's instinct and behavior is similar to that of a wild animal's, like when he knows who he has to fight before he even gets to the battle. Even how his fights show this as he relies on his instincts and counter attacks. This compliments the way he views the world. He is most often seen smiling, except in a fight where he is forced to use all his power (and sometimes even then). Luffy also seems to rarely change personality wise. Because he views the world in a straightforward and simple manner, he occasionally is the only person who can see past events that have taken place and realize the true goal, yet at other times he can fall into the simplest of traps.

Haki Monkey D Luffy In One Piece

Luffy has awakened the ability known as "Haki" and is one of the few known people able to use all three different types. Luffy was identified to possess this mysterious ability by Blackbeard after their first encounter in Jaya. He first showed the ability to actually use it when he knocked out Duval's steed, Motobaro, without actually hitting him. Since then, he showed increased but irregular usage of it, with very little to no control, as the series went on. It was only after the Marineford War, when he started training with Silvers Rayleigh, that he actually learnt about Haki and how to control it. Though it was stated that 2 years was too short a time to learn the basics of Haki, Luffy has shown a natural affinity for the ability, learning it in 18 months. Since reuniting with his crew Luffy has been shown to be conciously, actively, and easily using Haki in combat.

Haoshoku Haki

Haoshoku Haki Monkey D Luffy

He is able to use Haoshoku Haki, a type of Haki possessed in one in a million people. Luffy used this ability several times in the series, as it was the type of Haki that manifested the earliest. The first time Luffy was identified to have possessed this type of Haki was when he stopped Boa Sandersonia from smashing a petrified Marguerite, although he first showed possession of this type of Haki when he scared off Duval's bison steed, Motobaro.

When he protected Bentham from being attacked by wolves back at Impel Down (Level 5) Luffy released his Haki unconsciously. During the war at Marineford, he also used another burst of Haoshoku Haki when he saw Ace about to be executed, which knocked out a lot of individuals, whether Marine or pirate. This made it clear that Luffy, setting aside his identity as the revolutionary Dragon's son, is also a serious threat as a pirate just by possessing Haoshoku Haki.

Before training under Rayleigh, Luffy displayed limited to no control over this ability, and did not seem to realize he had it, but used it on instinct whenever it seemed to be most needed, and could still use it even when extremely injured.

With this training, Luffy has demonstrated the ability to focus his Haoshoku Haki, knocking out a small group with a quick glare without affecting anyone else. A possibility of Luffy's Haoshoku Haki is that he can tame large animals as he was capable of taming all the animals of Rusukaina Island, and tame the Kraken, which he did with great success in a very short time. Up until the fight with the New Fishman Pirates, Luffy has only used Haoshoku Haki when he needs to get people out of the way with minimum damage. The true extent of Luffy's Haki is seen when he knocks out 50,000 of Hody Jones' men.

Kenbunshoku Haki

Since training with Silvers Rayleigh, he appears to have gained significant proficiency in Kenbunshoku Haki, allowing him to tell what an opponent intends to do. He was able to dodge a bullet shot point blank by Demalo Black as well as laser projectiles fired by a Pacifista. His proficiency with this skill is truly shown when he was able to completely avoid Hody Jones' Yabusame without effort. Luffy also displayed being able to discern Caribou's presence within the Ryugu Palace, even asking if Zoro and Sanji can sense it too.

Busoshoku Haki

Busoshoku Haki Monkey D Luffy

Luffy seems to have also mastered Busoshoku Haki, which has been shown to darken his body (or parts of it) and harden it. This is first shown being used when he defeated a Pacifista with a single Haki imbued punch used in conjunction with his Gear Second. He is also able to use his Gear Third in conjunction with his Busoshoku Haki, being capable of knocking out a giant beast such as the Kraken easily, despite the great disadvantage of being under water (where his power was considerably weaker). After he used this, he did not turn into his child-like form. Another demonstration of Luffy's Busoshoku Haki is during his fight with Hody Jones, where he was able to harden his arm, leg, and forehead for both strong offensive and defensive measures. The defense of his Busoshoku Haki, however, is not absolute as shown in his fight with Hody Jones, where it was revealed that while it is good for reinforcing his near immunity against blunt attacks, it is currently not strong enough to defend against sharp objects, such as Hody Jones' shark teeth.

After the air bubble was produced and merged with Noah, Luffy used Busoshoku Haki combined with Gear Second to perform "Gomu Gomu no Red Hawk", which causes his fist to ignite into flames and create an explosion after it hits the target.

Luffy was later seen being able to knock back a Logia user like Caribou at considerable distance, something he was never able to do before the timeskip, without exploiting the Logia Fruit's weakness. He was also able to grab Smoker's arm in its smoke state as if it was solid and was also able to grab and punch Caesar Clown in his partial Logia state.

Relations Luffy With Straw Hat Crew

Because he is the captain, he always gives the best relationship for all crew.

To find such loyal companions... your son is indeed amazing... Dragon.

Recruited all the crew mates personally, Luffy cares tremendously for his crew. As far as captaincy to Luffy is concerned, he sees his other crew mates as equals in contrast to other pirate captains, who mostly sees theirs as subordinate underlings (his crew mostly calls him by name, rather than with an honorific or "Captain"). In fact, it could be argued that he is the only one that is generally beaten up and ordered around on the ship as several members of the crew have shown, especially Nami who never hesitates to give Luffy a beating for his idiocy (albeit, in comedic fashion). Luffy only pulls rank when he wants to go "adventuring", despite what his crew thinks, examples being when wanting to go to Skypiea and following the swaying needle to the New World.

Much like his idol, Shanks, Luffy is the kind of benevolent pirate captain who does not seek to actively harm others unless they give him and his crew (or anyone he cares about) a very good reason to. However, during the Jaya arc he was willing to start a fight with Blackbeard over a difference in opinion on pie. And as the Straw Hat Captain, Luffy has utmost faith in his crew.

Gomu Gomu no Mi Devil Fruit Monkey D Luffy

Luffy has gained extraordinary stretching powers from eating the Gomu Gomu no Mi (lit. Rubber Rubber Fruit, Gum-Gum Fruit in the English dub), which is one of the rare and legendary Devil Fruits. 

Gomu Gomu no Mi Devil Fruit 

After consuming the Gomu Gomu no Mi, Luffy's body became like rubber, giving him the ability to stretch long distances. Having trained hard for ten years, Luffy is able to supplement his stretching powers with immense strength, agility, and creativity in combat. His fighting style is largely improvised, and heavily reliant on his Devil Fruit. It should be noted, Luffy cannot automatically stretch his limbs (like superheroes with stretching powers, i.e: Mr. Fantastic or Plastic Man) since his body acts more like a rubber band, thus has to throw some force into it in order for his limbs to stretch out, though it seems that he has managed to be able to do it automatically after the time-skip. However, he can hold his limbs outstretched for a long time, as seen when he reaches his arm out about half a mile to retrieve Usopp from falling through the Sea Clouds. Luffy uses his stretching power in ingenious ways. 

Gomu Gomu no Mi Devil Fruit 

He is able to use the malleable stretchiness of his limbs to gain tremendous velocity and hit enemies with devastating impact. His rubber body is also extremely durable and virtually immune to blunt objects such as bullets (in One Piece, bullets are still round pellets, except for Don Krieg's), punches and electricity, bouncing off his body harmlessly or canceling out attacks. It's even become a running gag that people find out the hard way Luffy is made of rubber when they shoot at him, only to have the bullets bounce right back. Another running joke is that whenever Luffy's body is in peril that would kill a normal human, he says that he's made of rubber, so it's okay, or acts like something was a small problem despite the person trying to kill him, such as being shot in the heart. However, he is still normally susceptible to sharp objects such as swords and knives as well as nonphysical attacks like heat, cold, dehydration, and poison (though after the timeskip, Luffy has shown a strong immunity to poison due to his fight against Magellan in Impel Down). Not only can he use his ability to increase the range and strength of his attacks, but he can also use it to restrain and even control foes like puppets.