Sabo, Luffy, and Ace swore their brotherhood when they were still kids. The three were at Mt. Corvo when they took the oath of brotherhood. Due to Luffy being the youngest of the three, Sabo and Ace cared greatly about him. They didn't want their younger brother to face any problems.
The brothers would spend their time causing ruckus and hunting down mountain beasts. All three of them wanted to be pirates and each of them started their journey at different times. Ace and Sabo are really similar to each other in a lot of ways, and in this post, we will be talking about their similarities and differences.
10 Similar: Devil Fruits
The first of the similarities between the two brothers is that they possessed the same devil fruit. Sometime during his journey Ace came in possession of the Mera Mera no Mi. The devil fruit is a logia type that granted him the ability to control flames freely. Ace gained his epithet "Fire Fist" due to his popular attack of the same name. After Ace's death, the devil fruit fell into the hands of Doflamingo. He used the devil fruit as a bait to trap Luffy in the Corrida Coliseum. However, Sabo was there to help out Luffy. Sabo participated in the tournament under the alias of "Lucy." He ended up winning the tournament and he ate the Mera Mera no Mi.
9 Different: Power Level
Ace and Sabo might possess the same devil fruit, but both of them didn't have the same power. It is pretty clear that Sabo is the more powerful of the two brothers. Sabo is the current no. 2 of the Revolutionary Army and he has risen through the ranks in a very short time. Ace was the second division commander of the Whitebeard Pirates. Ace was even offered the position of a Shichibukai, but he turned it down. He has some noticeable feats to his name, but his power level is not on the same level as Sabo.
8 Similar: Admirals
Sabo and Ace have come across numerous strong opponents, but none so strong as the Navy Admirals. At Marineford, when Ace was finally freed, he fought against Aokiji and Akainu. His fight versus Akainu ended in a very bad way, because of his inferior devil fruit and Haki. On the other hand, Sabo fought against Fujitora at Dressrosa and he was certainly more impressive than Ace in his fight. Sabo didn't even have perfect control over his devil fruit, yet he managed to perfectly stall Fujitora to buy Luffy some time. Again, this just highlights the difference in the power of the two brothers.
7 Different: Conqueror's Haki
Another thing that separates Ace and Sabo is their Haki. Ace and Luffy are among the few people who are capable of using all three types of Haki. Ace used Conqueror's Haki against Bluejam Pirates and knocked them out. He has been confirmed to be a user of Armament Haki in his novel, and it is fair to assume that Ace has Observation Haki as well. He had been in the New World for a long time, so it's only plausible to believe that he would have Observation Haki as well. Sabo has been shown as a user of Armament and Observation Haki only.
6 Similar: Appearance
Sabo and Ace had a similar pattern to their appearance in the series. Ace appeared during the Alabasta arc when Luffy was going up against Crocodile, who was destroying the Kingdom of Alabasta. Ace remained with the crew for some before he went his own way and he gave Luffy his vivre card. Sabo appeared at Dressrosa and at that time Luffy was going up against Donquixote Doflamingo. Sabo left Dressrosa after the Doflamingo was taken.
5 Different: Sabo's Superior Bounty
Sabo was the first brother who set out to sail. After Sabo could not take his parents' pressure anymore, he left them and decided to sail before Luffy and Ace. Ace was next in line and he sailed several years after Sabo. Ace gained a lot of fame and he was one of the Super Rookies of his generation. Ace had a bounty of 550,000,000 beris which is one of the highest bounties in One Piece.
Sabo's bounty was revealed much more recently and his bounty supplants that of Ace. Sabo's current bounty is 602,000,000 beris, and it will definitely increase as the Revolutionary Army is making big moves.
4 Similar: Luffy's Protectors
Luffy has a knack for getting into trouble and more often than not, he comes out of the problem. However, there have been times when Luffy has had to rely on his brothers to protect him. Ace clashed against Smoker at Alabasta, who was chasing after Luffy. Ace allowed his brother to escape from the Marine Captain. Ace protected Luffy from Akainu as well. He jumped in front of Akainu's attack to save his little brother. At Dressrosa, Sabo helped Luffy a lot. Sabo clashed with Fujitora and the other Marines and stalled them till Luffy fought Doflamingo. Sabo also saved Luffy from Burgess' attack.
3 Different: Paths
Despite all of the three brothers wanting to become pirates, only two were successful. Actually, it was Sabo who first set sail, but a passing Celestial Dragon ended his dream preemptively. He grew up to become a member of the Revolutionary Army. On the other hand, Ace was successful in becoming a pirate. He led his own crew and they were known as the Spade Pirates. Ace gained a lot of fame and the World Government also recognized his power and offered him the role of a Shichibukai, but Ace turned it down. Afterward, Ace joined the Whitebeard Pirates and became the second division commander.
2 Similar: Will
Ace, Luffy, and Sabo might not be connected by blood, but they consider each other brothers and their bond is unbreakable. Ace and Sabo were always on the lookout for Luffy. They protected him from everything. After Sabo was presumed dead, Ace took it upon himself to protect his younger brother. Ace ended up sacrificing his own life for the sake of Luffy. Sabo inherited Ace's will to protect Luffy from any harm.
1 Different: Lineage
Ace, Sabo, and Luffy were without a doubt very close to each other, but all three belonged to different bloodlines. Ace is the son of Pirate King, Gol D. Roger. Luffy is the son of Dragon, the most wanted man and Sabo is the son of Outlook III and Didit. Out of the three Sabo belongs to a noble bloodline. Regardless of their different bloodlines, the three brothers had an unbreakable bond.