Sabo is one of the brothers of Ace and Luffy from Dawn Island. He grew up to join the Revolutionary Army of Monkey D. Dragon.
Sabo grew up as a noble on Dawn Island in the Goa Kingdom. Feeling neglected by his parents, whose only true interest in Sabo was having him protect their status and fortune, Sabo fled from their home in High Town to the Gray Terminal.
Sabo began working with Ace 5 years prior to meeting Luffy. Sabo and Ace spent those 5 years gathering money in order to buy themselves a pirate ship to escape the Goa Kingdom. They collected their fortune through thievery and performing odd jobs.
The character of Sabo is a supporting character in the One Piece series that was created by Eiichiro Oda. The series first began serialization in Shueisha's Weekly Shōnen Jump on August 4, 1997. He first appeared during the Dawn Island Arc that began in Volume 59.
His first appearance was in One Piece Volume 59 CH. 583 "Gray Terminal - The Final Destination of the Uncertainty", and his first anime appearance was in One Piece - Episode 494 "Here Comes Sabo! The Boy at the Gray Terminal!". His character in the Japanese series is voiced by Junko Takeuchi, and the U.S. dub produced by FUNimation has not been announced.
Sabo first met Luffy during a conversation with Ace in regards to their treasure and plans of becoming pirates. Hoping to create a bond through revealing his own plans to become a pirate, Luffy revealed himself to the two. Originally Sabo and Ace had planned on killing Luffy, but neither felt comfortable directly killing a person, telling the other to do it. They were interrupted before coming to a decision by the distant approach of Porchemy, a pirate in Bluejam's crew that Ace had recently robbed. Porchemy manages to kidnap Luffy while the other two escape. Convinced that Luffy knows where Ace and Sabo's treasure is, Porchemy begins to torture Luffy. When Ace and Sabo learn that Luffy has resisted Porchemy's torture out of an act of friendship to the two, Sabo and Ace felt compassionate towards Luffy and came to his rescue.
After their confrontation with Bluejam's crew, Sabo decided that it was no longer safe for him to live in the Grey Terminal with their treasure, so Ace and Luffy invited Sabo to live at their home with the mountain bandits. In the following days, the trio sparred in the jungle, 100 matches each every day. In terms of strength, Sabo seemed to be only slightly below Ace, yet far above Luffy, with one day indicating he had beaten Luffy in 50 fights, beaten Ace in 24, and lost to Ace in 26 fights.
One day, while causing trouble in Central Town, Sabo was spotted by his nobleman father, who had presumed his son dead. While Sabo was fleeing from the authorities, his father called out to him and told him to come home. All three brushed off Sabo's father while fleeing the city, but upon returning to the forest, Luffy and Ace began to interrogate Sabo. Sabo revealed that he is not an orphan, as he had led the two to believe, but a noble, and explained to them why he had left. The conversation eventually evolved into planning their future. Sabo revealed his dream of writing a book about his future adventures, vowing to learn how to navigate. They soon realized that all three wanted to be captain, but Ace told them they would make a decision when the time for it was ready.
The conversation evolving once again, Ace pulled out a bottle of sake and three cups, he told them that by sharing a drink they could become brothers. All three drank their sake at the same time, creating an unbreakable bond, vowing that no matter what happens, they will always be brothers.
The three brothers continued to live in harmony for a while, moving out of Dadan's house and into a tree house, protecting each other and building up their fortune. There happy life came to an end when Sabo's father recruited Bluejam to help kidnap back his son. In exchange for his brothers' safety from Bluejam, Sabo agreed to submit to his father's will and return with him to High Town.
Back on Bluejam's ship, Bluejam assured Luffy and Ace that it was in Sabo's best interest for the two to leave him alone. Luffy and Ace decided to take his word for it and gave up any attempt to rescue Sabo. Instead they began to work for Bluejam, claiming he didn't care about Porchemy, he was only interested in strong people (Luffy and Ace), regardless of their age. Unbeknown to them, Bluejam had them strategically placing bombs around Grey Terminal for an upcoming plan to burn the entire town in an effort to please the World Nobles who would soon be visiting the kingdom.
In High Town, Sabo was abused by his father and brought back to his home where he met his new, adopted, brother Stelly, a promising son of another noble family who could no longer raise him. That night, in their bedroom, Stelly told Sabo about the plan to burn down Grey Terminal. Sabo immediately set out to investigate, within in a day he discovered that the people of High Town were even more despicable than he had imagined, and so he once again fled from High Town. On the night of the fire, near the outskirts of the city, Sabo bumped into a not yet famous Monkey D. Dragon, where the two had a brief exchange about how horrible the people of Goa were.
Sabo is once again returned to his home in High Town where his father scolded him, telling him that he could never escape. Soon after his father left, Sabo began preparing for his final escape. The next day, as the World Noble approached Goa Kingdom in his boat, Sabo set out on his adventure in his own boat, hoping to fulfill his dreams. The fun ended when the World Noble is disgusted by Sabo and sinks his ship. The reader is led to believe that Sabo was killed, as his hat floated on the water's surface alongside the scraps of his former boat.
It should be noted that Sabo's body is never seen, and on the night following Sabo's alleged death, Dragon met back up with the other revolutionaries carrying an unseen body in critical condition.