Arlong grew up on Fish-Man Island together with well known fish-men like Jinbei, Hachi and Fisher Tiger. Sixteen years before the current storyline, Arlong used to be part of the Sun Pirates, together with his rival Jinbei. After the death of Fisher Tiger, the crew's captain, the group split apart. Arlong and Jinbei both went their separate ways. Jinbei climbed the ladders and became powerful enough to become part of the Royal Shichibukai and Arlong created his own pirate crew named after himself: the Arlong Pirates. He soon left the Grand Line to look for easier targets, he eventually stumbled upon an island named Commi Island. Commi Island was a large island with small villages and towns, the perfect place to extort money. It was a simple and peaceful Island until the Arlong Pirates took over, setting many strict and harsh rules.
The first village the pirates encountered was Cocoyashi Village, hometown of Nami. Arlong proceeded to extort and threaten people, amassing a small fortune in the process. Nami and Nojiko's adoptive mother, Bellemere, only had 100,000 Belli. Arlong arrived at Nami's home, Bellemere tried to fend him and his crew off but was easily beaten having her arm crushed by Arlong in the progress. Because the t wo girls were not home during that time, Arlong didn't extort ask for any more money. The villagers urged her to use the money for herself, telling her they could hide the children. But Bellemere told Arlong that the money was for her two daughters, seeing that by denying the existence of her daughters she would also be turning her back on her daughters and her role as a mother. Rather dying than not call herself a mother, Arlong shot her at point-blank range in front of her children as an example of disobedience.
He then noticed the map Nami had drawn, instantly recognizing the unrivaled talent this girl had, Arlong kidnapped her. He forced Nami to become a part of his crew as a map maker, and told her that if she brought him 100,000,000 belli he would free her village and everyone in it, including her adoptive sister Nojiko. He wanted Nami to make a map of the entire world, Seeing that by using these maps he's able to conquer the entire world.
Arlong Park Arc
Eight years have passed since then and Nami has matured into a woman. She took up thieving in order to get enough money to free her village, by the time One Piece begins Nami is almost at the end off her bargain. Arlong knowing that Nami has almost reached the 1 million, tips of a corrupt marine captain that Nami is hiding a huge treasure. He uncovers it all and proceeds to confiscate all the money. Nami runs back to Arlong and accuses him of sending the Marines to look for her money. But Arlong denies it, claiming he never broke their deal and tells her that if she want her village back, she'll just need to start again from scratch.
One of Nami's latest targets was Monkey D. Luffy. Luffy, who followed Nami after being robbed by her, saw Nami brutally stabbing Arlong's tattoo on her arm in desperation. Angered by the obvious suffering Arlong had wrought against her, Luffy stopped her from hurting herself and unquestioningly accepted her plea for help. Luffy together Zoro, Sanji and Usopp confront Alrong and his crew. Luffy manages to take down all of Arlong's weaker crew members but lodges his feet in the concrete during the process. Which Arlong notice and takes advantage of by uprooting the gravel around Luffy's legs and throwing him into the ocean, proclaiming that it is a "game" and the other Straw Hats must beat the fish men to save Luffy.
The only members left are the powerful elite. Zoro takes on Hatchan despite his wound and fever but manages to win against Hatchan's six-sword style. Sanji tries to save Luffy but is brutally beaten by Kuroobi every time he tries to help Luffy. After Nojiko and Genzo come to aid Luffy, Sanji forces Kuroobi up to dry land and kicks him into submission. The last fish-man left is Chuu, which Usopps manages to beat with a combination of deceit, sniping and running. While Zoro, Sanji and Usopp were able to defeat their opponents, they then try to take on Arlong. Their individual battles left them injured and exhausted, allowing Arlong to beat them quite badly. Nami arrives in the midst of the battle and sides with the villagers to fight Arlong. Luckily Nojiko and Genzo revive Luffy and Sanji frees him of the rock on his feet to finally fight Arlong one on one. A rough battle ensures as Luffy and Arlong trade blows around the park.
Arlong and Luffy battle for a while, where it constantly seems that the other is on top. Both take damage during the fight: Luffy gets bitten and Arlong's teeth get shattered (although he grows a new pair in a matter of seconds). During the battle Luffy manages to anger Arlong to such a degree he goes into a uncontrolled fit of rage. Arlong gains a slight edge against Luffy, but his rage makes him careless and destructive. Not paying attention to the destruction he wreaks upon his own home. They continue their battle until Arlong forces Luffy to escape into a room at the top of the tower where Arlong reveals is where Nami slaved on making maps for him. Luffy starts to tear the room apart, Arlong tries to stop him with a final attack but Luffy is quicker on the draw and smashes Arlong through several floors, pounding him into the ground on the last floor. The impact destroys the park in the process and when the dust clears Arlong is seen laying on the ground, defeated.
Later, Arlong and the rest of his crew are arrested imprisoned by the Marines. Hachi was the only one to escape. Arlong has been mentioned a lot of times since his appearance. These references are mostly made by fish-men and/or former Sunny Pirates crewmates. One such case is that Jinbei holds some contempt towards Luffy for beating one of his former close allies. After the timeskip Arlong is mentioned as the inspiration for the New Fishmen Pirates. Since arriving in Fishmen Island, Luffy has constantly been called the man who crushed Arlong's dream.
Powers and Abilities
Arlong is a member of the fish-men race, because of this he has physical attributes that far exceed a regular human being. Fish-men are stated to be ten times stronger than a regular human and are able to breathe on both land as well as underwater.
Even by fish-men standards, Arlong is very powerful He possesses superhuman strength, speed, durability and stamina. Arlong also possess superhuman jaw strength as well as durable teeth that regrow in mere seconds. In his fight with Luffy, he used a giant sawlike sword, the Kiribachi , with great proficiency, as he was able to cut even a building with it. Predictably, as formidable an opponent as Arlong is on land, in the water he is nearly invincible. Arlong also has some kind of berserk mode when he gets angry. This is shown by his eyes changing to eyes similar to a sea king.