Garp is one of the major figures, along with Sengoku, Shiki, and Whitebeard, from the times when Gol D. Roger was still alive.
Garp is a tall, tan, broad-chested, muscular old man who is bearded and has a scar on his left eye. In the anime, his eye colours were revealed to be blue and his hairs are gray, unlike the manga, where they are white. Due to the fact that he had appeared in Romance Dawn, Version 2 with his face exposed, he wore a dog mask when he was first introduced (so fans would not realize he was Luffy's grandfather).
When this fact was revealed, he discarded the mask. Since then he has only worn the mask upon making entrances. Garp was also seen smoking cigars. Garp is the only vice admiral along with Tsuru to have special shoulder-pads; his are black and red whereas the standard color is blue.
When he was younger, twenty-four years ago, Garp's hair and goatee were still black, with his sideburns beginning to whiten. He also wore a much darker double breasted suit with a white shirt and a red tie, but he already had the scar above his left eye.
When he was a child and a very young Marine, Garp greatly resembled Luffy, but he still retains his scar on his left eye. As a child, he wore a tropical-like button shirt with shorts. He is seen wielding a pipe staff and carrying a treasure chest while riding a tiger he tamed.
After the timeskip he doesn't change much, but in the anime his hair is now white, as it was in the manga before the timeskip.
Garp displays an intelligence level that is equivalent to that of Luffy's; however, Garp seems somewhat more absent-minded than his grandson. Due to his hot temper, he is unable to accept excuses (and is exceptionally poor at creating his own) and at times likes to enforce his point of view on things with his fist. Garp also has his own laughter style: he adds either Bwa or Wa before the haha part.
He, like his grandsons, has an extreme fondness for food; which in his case is specific to donuts and rice crackers.
He also is somewhat of an eccentric person with a rather strange approach to things; rather than entering through doors, he finds that bursting through walls is the cooler thing to do. But then in the end, he will only end up ordering his subordinates to repair the damage he caused. He also refused promotion to admiral on several occasions, because he felt being a vice admiral was fine (it should be noted that being an admiral would most likely reduce his ability to do as he pleased).
Garp is a supportive person most of the time as shown when Shiki claims that the Pirate King will die in the weakest sea is humiliating, and Garp in turn says that East Blue is a symbol for peace. When Ace was a troubled kid during his childhood, he asked Garp a question whether he should have been born, Garp told Ace that he will be able to find the answer if he continues living.
Even though Ace was the son of his most formidable rival, Gol D. Roger only requested for him to hide his son. Though Garp hesitated at first, after witnessing the noble sacrifice of Ace's mother, he complied to Roger's wish. Not only that, he adopted Ace as his own grandson, treating him the same as he would towards Luffy, albeit in his own brand of tough love. When Ace wanted to see him as merely a guardian, he insisted that Ace is his grandson and that he is his granddad. When Ace was at the execution deck, he even sat next to Ace, talking to him and giving some moral support.
Although Garp is loyal to the Marines and wanted his grandsons to become one, in the end he chose family over duty, showing that he follows moral justice. Another irony is that despite what Garp wanted out of his grandsons, he entrusted their care in that of a criminal, against the moralities of justice. Showing despite being a true believer of Justice, would also turn a blind eye to them as well (such as adopting Ace from Roger and not turning in Dadan and her gang); this proves that unlike his fellow marines, such as his friend Sengoku, Garp does not believe that one's lineage would be considered a threat to the world. However, considering that Luffy and Ace seem to speak fondly of Dadan, and Garp did once call her a friend, it can be possible that Dadan is not so bad as she is implied to be. Perhaps Garp believed that she did not deserve to be punished either way, even though the law demanded it (similar to how Garp saved Ace because he believed Ace did not deserve to die, though the law dictated otherwise).
During the Impel Down Arc, Garp comically (if not mocking Sengoku) showed to be very proud of his grandson when heard the news about the riot caused in the prison. It showed that, despite their choice to become pirates, Garp holds some admiration of how strong they became.
As the "Hero of the Marines", Garp is overall very well-respected for cornering the Pirate King multiple times. While Garp seems devoted to his duties, he has his own sense of justice and does not always obey orders given to him. Aokiji is indebted to Garp and is impressed that Garp refused several promotions, while Akainu has earned the vice admiral's hatred for killing Ace. He was requested to remain behind as an instructor due to his fame will be influential for recruits.
Garp has problems with respecting his superiors and such is the case with then-Fleet Admiral Kong 27 years ago and former Fleet Admiral Sengoku.
His crew and others around him often react with shock or uncertainty when hearing his reactions to things. At times he will say things that are random or seems to be unaware of the true extent of what is going on around him. At the Marine Headquarters, many of the other Marines are afraid of him for his reputation and habit of controlling things through his fists. Interestingly after ordering his crew to rebuild a wall Garp himself had just destroyed, his men refused to do so unless he helped as well. This is the most insubordinate behavior displayed amongst a marine crew, however his men are not disloyal. Despite Garp telling his entire crew about his relationship with Luffy and Dragon, the general marine populous was unaware of it until the war with Whitebeard, suggesting his men kept it secret. This casual but loyal relationship with his crew is likely a parallel to the Straw Hats.
Garp's right hand man is a marine of unknown rank, who is usually seen with him. In the anime his name is Bogart, although his name has not been revealed in the manga so far. It seems that Garp and Bogart have been together for at least 27 years.
He is also the mentor of Coby and Helmeppo, he keeps them out of trouble and ensures they are not slacking off. They both come to admire him, even though he maintains a highly brutal clutch on them because they would not be where they are without him. He was horrified when Coby shouted out to stop the killing at Marineford during the Whitebeard war.
Sengoku
A typical moment between Garp and Sengoku.
As a hero of the marines, Garp has high respect amongst the marines, even with Fleet Admiral Sengoku. In fact, in the past, Garp and Sengoku seemed to be very good friends, albeit that Sengoku was a little annoyed with Garp's tendency to act on his own accord whenever Roger was involved. However, currently, as with the revelation that both Monkey D. Luffy and Portgas D. Ace are Garp's grandsons (Ace being adopted), as well as Luffy's multiple actions in such a short time, Sengoku is losing patience with Garp, but the two Marines still share a close friendship even though Sengoku seems somewhat more hapless at his friend's silliness.
Garp, on the other hand, seems to merely laugh it off and enjoys getting on Sengoku's nerves. Notably, Sengoku's biggest annoyance is Garp's refusal to keep his family under control even when threatened with the consequences; Garp simply does not believe the life of an old man could ever atone for the actions of his family. When or how long Sengoku knew of Garp adopting Ace is unknown, but Sengoku found out that Ace is the son of Gol D. Roger. Also, how long Sengoku knew about Luffy and Dragon's familial relationship to Garp is unknown, but Sengoku had no problem revealing all of it worldwide. Even including the fact that Garp was about to try to kill Akainu for killing Ace, it seems that none of this has affected Garp's standings in the Marines even when his relationship with both Dragon and Luffy went worldwide, as Kong insisted that Garp's title and records be used to recruit new Marines.
Family
Monkey D. Dragon
Dragon is Garp's son. No direct interactions have been shown, however, he seems casual about the idea of his own son being a Revolutionary and wanted by the World Government. He seems to have communicated with him at least once since the Loguetown Arc due to Garp knowing of Dragon's role in saving Luffy from Smoker, however this can be disputed since it is most likely that Smoker reported the incident so it's only natural that Garp would find out. Garp denied Luffy and Dragon's relationship from the world in the hopes to protect his grandson, but by the time Sengoku made it public, Garp simply states that Luffy already has such a reputation that his connection to Dragon is irrelevant.
It is clear that both Garp and Dragon have different assessments of the East Blue. While Garp perceives it as a rather peaceful place, Dragon expresses his disgust with Garp's view of "peace" since it was nothing more than a form of oppression authorized by the law in places, such as Tequila Wolf and the Goa Kingdom, evidently have common people that are put in horrible living conditions.
Monkey D. Luffy
Garp appears on the news about Luffy's return.
Garp seems to hold high standards for his grandson Luffy, and gets mad at the slightest mistake he makes, even when his own are sometimes no better (i.e. telling off Luffy for falling asleep and proceeding to punch him yet falling asleep himself). This often leads Luffy to receiving the force of Garp's punches, and due to these experiences, he has become afraid of his grandfather. Garp also claims Luffy was poisoned by Shanks with ideas of becoming a pirate, as Garp wanted Luffy to be a great Marine like him. However, Luffy claims he told Garp that even as a child he wanted to be a pirate. Nevertheless the two get along quite well. As Nami stated at the time of Garp's departure, there seems to be an amazing ego that runs in Garp's family. Garp left Luffy in Dadan's care as a child. This is how he met Ace.
Garp appears to find a great source of pride whenever Luffy commits outrageous acts. Garp even found it amusing when he learned that Luffy had infiltrated the great prison, Impel Down, in an attempt to rescue Ace. However, when he learned that Luffy broke out of Impel Down (taking many infamous prisoners along with him) and headed straight to Marineford, where the Marines are currently waging war against Whitebeard and his crew, Garp's immediate expression was that of shock. This implies that he cares for his grandson's well-being. However, when Luffy was on the verge to saving Ace, Garp jumped in and refused to move, on the grounds of his Marine duties. In the end though, the love for his grandson proved to be stronger than his sense of duty, since he permits Luffy to hit him without even trying to avoid the punch.
Being Garp's grandson has lead Luffy to become a prime target for Chinjao's grudge in Corrida Colosseum, who wanted to take revenge for Garp nearly killing him.
Portgas D. Ace
Garp adopted Ace from Gol D. Roger, who requested Ace does not deserve to be treated as a criminal just because of his family ties. While Garp initially thought of adopting Ace as a preposterous idea, he eventually agreed to Roger's final wish, as the latter pointed out that after countless confrontations, he trusted the vice admiral much as a friend. Indeed, Garp seemed troubled when Ace was about to face death as he claimed he had no pity for Ace as he was a pirate but believed family is different. He cares about him deeply, openly crying for his grandson as he's about to be executed for being a pirate, angrily asking why he could not have just been a Marine. Garp even mentions to Fleet Admiral Sengoku that if he could have done anything to stop Ace's execution he would have done so already. In fact, Garp wanted to kill Akainu in revenge for killing Ace.
When Ace was an infant, Garp would use his vacation and often visit the village and pull funny faces to cheer him up. Later when Ace was a troubled child that beat anyone up that insulted his father, Garp seemed amused with Ace, yet Garp never scolded Ace for his actions. After Luffy, Sabo and Ace got along well, Garp would sometimes visit them and train them in a harsh manner (i.e. beating them all up).
As well as Luffy, Garp had high expectations for Ace to be a strong Marine, but is disappointed that he chose the life of piracy, which incidentally sent him to Impel Down where they were talking about the issue. However, Ace refused the idea that he and his younger brother could have ever been Marines, with their fathers' restless blood in their veins.
Enemies
Gol D. Roger
Back when Gol D. Roger was alive, Garp managed to corner him many times. As such, they have a long history against each other. However, when Roger was about to be executed, after turning himself in due to his terminal illness, he made a final request to Garp. He asked Garp to take care of his unborn child, as he did not deserve to be condemned as a criminal because of his father's crimes.
Due to their countless clashes, Roger came to see Garp as much of a friend as the rest of his crew. Garp too seemed to have some form of respect for him as he not only protected Ace but showed signs of disappointment from Ace's decision to disregard Roger as being his father. Also, Garp acknowledged Roger's strength, stating that although Roger was extremely reckless, that's what made him into the pirate king. Garp also told Dadan that although he is a marine, he could never come to hate Roger.
Whitebeard
Whitebeard seemed to know Garp and know his strength when he calls him as Garp not brat unlike Crocodile, Akainu, Aokiji, Kizaru, etc. Garp did not let Marco pass through to get to Ace's execution platform meaning he did not care how fearsome Whitebeard could be after seeing that.
Chinjao
Chinjao was nearly killed by Garp, leading the elder, former pirate to hold a grudge against the former vice admiral, and by extent, Garp's descendants.[8] Chinjao also reveals that in Garp's younger days, pirates referred to him as a "Demon".[9]
Other Pirates
Over his many years as a Marine hero, Garp has made many enemies with pirates over the sea, such as Shiki and Shakky. He felt neither remorse nor pity for any of these pirates, as they are criminals. He also bears a grudge against Shanks, because Garp believes he is the one who influenced his grandson, Monkey D. Luffy to become a pirate.
No wife has been named for Garp, however the supplement Grand Line Times left a "?" in place of one. Also as a person carrying the Will of the D., he may be related somehow to others also carrying it.
Curly Dadan
As Curly Dadan is the leader of a bandit group, Garp blackmailed her to watch over Ace and Luffy as their foster mother, in exchange that he will turn a blind eye on their criminal activities, which is said to equal the numbers of stars in the sky. Despite Dadan having a fear and irritation against the vice admiral for leaving two children at her care, Garp claims that Dadan is a friend of his. This is ironic, as Garp claimed that he has no sympathy for criminals, and will arrest them at ease. Even in more recent times, Garp and Dadan continue to show a violent relationship that likewise harbors respect for each other and for the work they had in connection to both Luffy and Ace.
Sabo
It is unknown what Garp thinks of Sabo, but he does know about him since he is seen beating Sabo, Luffy, and Ace during "training". This is expanded a little in the anime when Luffy told Garp he, Sabo, and Ace had exchanged cups of Sake. He then decided to "train" Sabo like Luffy and Ace.
Abilities and Powers
As a vice admiral of the Marine Headquarters, Garp had command over all lower ranking soldiers. An example of this is when after Morgan escaped, he was able to take away two of Ripper's subordinates (Coby and Helmeppo) and make them his own subordinates instead due to him having the higher rank. Also as a vice admiral, he had the potential to be called upon to be one of five vice admirals leading a fleet of ten battleships during a Buster Call.
Garp is one of the most powerful fighters seen in the series so far. Although rather old, Garp still possesses an incredibly high amount of physical strength. He is able to throw iron cannonballs as if they were baseballs (at faster than cannon speeds), break through brick walls and cannon stands with his fists, and both carry and throw a gigantic ball and chain many times bigger than the Thousand Sunny. Garp also has a monstrous punching ability at his disposal, with his epithet, "Garp the Fist," vouching for his punch strength.
In terms of combat, Garp has had several decades worth of experience in both combat and navigating the harshest oceans within the volatile "New World". He's also a "hero" of the Marines and as is known for cornering and fighting Gol D. Roger many times. Roger also stated that he and Garp had almost killed each other on numerous occasions.
He also has leadership skills, being a Marine vice admiral and the commanding officer of the 153rd Marine Branch.
In addition to his legendary strength, as seen when he was slashed by Captain Morgan's axe hand, he was able to recover only seconds later, with no obvious pain and apparently being oblivious to the fact he was struck at all. This was due to the fact he fell asleep before he was being attacked. He was able to get back on his feet after being punched by Luffy in Gear Second at point-blank range without losing consciousness (the punch was made possible only because Garp allowed Luffy to land the strike) and was still able to fight the Blackbeard Pirates along with Sengoku.
He has also been shown to be extremely fast as he managed to bypass all of the Straw Hats in order to get to a sleeping Luffy. It is evident Whitebeard respects Garp's strength as he mentioned him during his talk with Shanks. It should also be noted that Garp is not seen to carry any weapons, aside from the cannonballs that he throws, which implies that he is most likely a hand-to hand fighter. Another example of Garp's strength is when he shown to easily strike down Marco of the Whitebeard Pirates despite having his Devil Fruit abilities activated at the time, knocking him back which was something that Kizaru and Akainu seemed unable to do.
The extent of Garp's power and fame is evident round the time of the Battle of Edd War, three years before the future Pirate King died. It was revealed that he was offered the rank of admiral more than once, but repeatedly refused the promotion. Garp's subordinate at that time, Kuzan (later promoted to admiral), commented on how cool Garp was for refusing such an irresistible promotion to which he answers by stating that he does not need a higher position, and that it would reduce his liberty to do what he wants. While being officially ranked as a vice admiral, his power was once or still is enough to qualify him for the rank of admiral or even fleet admiral before he retired.
Similarly, when it was revealed worldwide that Luffy is Garp's grandson, Luffy's fame rose based on that fact alone, as Demalo Black attempted to use that as one of the strong points in his impersonation of Luffy, and Charlotte Linlin referenced to Garp when Luffy challenged her. Garp is also well aware of the existence of Haki, as evidenced when his grandson releases the Haoshoku. Haki throughout the area. Also, it was stated that all vice admirals possess Haki, so Garp can also use the ability. He is aware of Haoshoku Haki as said that "He did inherit it after all", when Luffy used it at Marineford.
Because Coby seems to have awakened Kenbunshoku Haki on his own, a Marine doctor recommended that Coby ask Garp how to master it, suggesting he has enough expertise in it to mentor others. However, in East Blue, he failed to predict Morgan's sudden attack because he was asleep.
With his Busoshoku Haki, Garp was able to injure Luffy several times, bypassing his rubber body. During the Battle of Marineford, he managed to punch and hurt Marco despite his regenerative phoenix form.
