Got elected and given an invitation to be a Shichibukai at Sabaody.
Ace refused the invitation and got into a fight against a Vice Admiral whom he defeated.
Unlocked Armament Haki during that fight.
By deduction, Ace accomplished this in his first year out as a Pirate, at the age of 17; this is the same age in which Sabo is also shown using Armament Haki and imo, the Manga makes them out to be parallels, 2 sides of the same coin which may be why Ace’s death triggers Sabo’s recollection of his past
Long beefore Ace dies, he visits Shanks, fought with Jimbei & Whitebeard and has become a Whitebeard Pirates; at this point in time, he’s regarded as a Super-Rookie (who is a Pirates who gains a 100m+ bounty within a year of reaching Sabaody) by Shanks, so it’s implied that he’d accomplished all this notable accomplishments between the age of 17 and 18.
By the time he’s become an established rank within the Whitebeard crew (probably spent at least 2 years in the crew), he fights Blackbeard and Ace at this point in time is a seasoned New World Pirate. Blackbeard says it’s been a long time since Ace has been hit and this is a Pirate who already knows how to use Armament Haki and we can guess Observation.
Ace may appear weak, but we shouldn’t forget he fought 2 of the strongest characters in the series; strong guys look weak against the strongest. We shouldn’t forget that Ace was probably not in peak condition against Akainu as he’d been imprisoned, tortured, probably unfed for days and fighting against a monster. He also never really got the opportunity to fight Akainu intelligently, therefore, it’s difficult to gauge just how strong he is. Even after the time-skip, he’s still somewhat held in high regard:
Chinjao regards Ace as the only one who could have become Pirate King 2 years after his death. (This is only qualitative)
Correspondingly, the next person he sees as capable of becoming Pirate King is the victor that led to Marineford, Blackbeard.
While we can’t quantitatively ascertain or determine his strength, we should probably appreciate that he was able to defeat a Vice Admiral by the time he reached Sabaody which not even Luffy pulled off.
Ace & Roger
Roger would never run, especially when protecting Nakama.
Roger didn’t care about the world, only about his Nakama, they viewed him as evil.
Grew up in similar circumstances like Ace, and that’s what made him Pirate King as Garp says.
He’s overprotective of his comrades; never runs from a challenge especially when to protect Nakama.
He didn’t care if the world accepted him, so they viewed him as evil due to his selfish nature.
Like Roger, his circumstances drove him to become Pirate King.
What’s being highlighted? It’s the fact that Ace and Roger were literally identical, carbon copies of each other. What Ace aimed to do, was exactly what Roger did, and that’s why he became Pirate King. The irony of it all is that while Ace hated his father, he was similar to him which is why Dadan say. . .”I guess you really can’t go against your blood” from hearing about Roger through Garp.
Why Ace Relinquished his Goal
On a final note, while Ace is considered the greatest potential to be Pirate King and someone who once had the ambition to achieve this, why did he relinquish his goal? Did he give up? Did he feel there was chasm in strength? The answer seems to lie in the fact that Ace found someone he considered greater than himself and something he sought out secretly.
Ace was rather morbid (suicidal even) and one of his goals in life was to determine whether he deserved to live. He was the son of a man whom the world hated, and all throughout his life, he was rejected and this was likely his purpose to become Pirate King, as a way to vent out his frustration on the world.
On meeting Whitebeard who out of the blue offered the chance to be a son and part of a family, he couldn’t resist; what he gained from Whitebeard was something Roger couldn’t give him and he hated him for this. His need for a father figure and for acceptance even if for a moment had him even hold on to the fact he was Roger’s son (whom was Whitebeard’s enemy). It’s only later he worked up the courage to reveal this to him, and even then, Whitebeard didn’t care. Ace couldn’t help but give his life for him.
What Ace sought out more than being Pirate King was for a family, happiness, and the Whitebeard Pirates did just that, it gave him comrades he could look at as brothers and a father to complete what he’d settle for as family.
Credits – HPsyche