Ace is somebody who inherited so much
I was reading the manga when we first met Ace in the Alabasta Arc so there may be a slight difference there.
The vibe we get from him initially is of someone who is chill and easy-going. He seems like somebody who takes everything in stride.
As we get to know him more, it makes more and more sense that Ace and Luffy are brothers. Even despite the clear difference in personality, they share similaries in both appearance and habits. He behaves like an older brother
Then in the Marineford Arc we find out this isn't true in the biological sense. They didn't even meet until Luffy was 7 and Ace was 10. Ace was the instead the son of the Pirate King, Gol D. Roger.
As we go through the arc, we see more of Ace's true personality shine through. The easy-going trait turned to a calm acceptance of his impending death. The anger he lets build up to throw harsh words, in a very desperate attempt to save his loved ones. The tearful gratitude that he has for being as loved as he is.
Then the flashback hits, and it makes sense.
So I'll seperate the things he inherited from those around, regardless of whether he wanted to or not.
Garp (and indirectly Luffy)
Garp is the first family Ace got. He may not have been his closest family, nor was he the family Ace valued the most. But he was family to Ace, and both of them are aware of this.
The habits, like sleeping mid-conversation and eating a gluttonous amount of food, are things that are clearly meant to be reminiscent of Garp and Luffy. You're meant to think "Oh, he's obviously related to them,"
Some of the stubborness, and Ace shows it can also be seen in bits of Garp, if I'm to be honest. They shout and scream, push and shove, if only to get their way (though Garp usually wins)
They also shared the 'tough love' attitude with Luffy, though Ace's is more verbal and Garp is both physical and verbal.
Dadan, the only real motherly figure in his life
Dadan was the woman who raised Ace since he was a baby. She was his foster mother and also the closest thing he had to a mother.
So I found it hilarious when I realise that his tsundere attitude was from Dadan. They both hide behind a shell of absolutely brutality and aggresiveness, trying their best to act like they don't care when they actually do.
They care deeply and value the people in their life strongly. They will cry for then, and they will fight losing battles for them.
Ace's aggresiveness comes from a lot of places but being raised by Dadan probably contributed to his zero-hesitation in showing it.
Sabo
Sabo was somebody that Ace initially found camaraderie with when they first met. They both wanted to escape the island they were on, leaving behind the connections and people they had there. They wanted to become someone new.
Once Luffy came into the picture, this list grew into protecting Luffy as much as they could. It was to look after him and be good big brothers.
After Sabo's 'death', Ace seems to try to take the weight of Sabo's responsibilities alongside his own. He already started showing signs when Sabo was forced to go back with his parents, but its more brutally obvious after Ace got the letter Sabo had sent them.
He took on the weight of being the kinder big brother, in Sabo's absence. He also tried to be more polite, and grow more responsible over Luffy.
It's seems like traits of his calm attitude may be attempts at replicating Sabo's level-headeness.
Whitebeard and the Whitebeard Pirates
Whitebeard was someone who valued the idea of chosen famiy above all else. This is something tat allowed those who felt alone and lost to find comfort in his version of a family.
Ace was haunted by his bloodline and he never truly got over it until he met whitebeard. There, he kept fighting and pushing, until he finally realised he wasn't gonna be hurt. That Whitebeard meant it when he said Ace would be his son.
So Ace, after a long series of murder attempts, adopts Whitebeard's mentality of found family, and fully disowns Roger as his dad. He got to make that choice, and he stood by it intil his death.
Portgas D. Rogue
Yes, I used her full name because she deserves everyounce of respect that I can offer this woman.
She also passed down her stubborness and determination to her son. Her short screen time was deicated to showing just how farshe would go for her child. She never hesitated, she never panicked. She just held on, and then cherished her son for the short time she had with him.
Ace held this same determination throughout his life. When he stood on in the face of danger he was always calm. Something I'd like yo believe he got from his mother.
Roger
He hated Roger alot, but there were still traits of his that he carried, which are, by far, pointed out the most.
Roger is someone we still don't know much about. All recollections of him are second-hand and can lean towards bias often. But there are a few people that did seem to know him well enough.
One of those are Garp, who notes that Roger and Ace both share the trait of fiercely protecting the people they love and care for, refusing to turn back and run if they were wronged.
So even though Ace hated Roger (understandably so), he still carried a part of him that allowed him to protect the people he loved.
...and also get himself fucking killed in the process [gunshot]
Luffy
Luffy is Luffy, in the end. He is a very interesting character on his own, but he is still as interesting in the way of how he impacts other people's lives.
With Luffy, Ace found someone who wanted him to live and keep on living. But that's just a surface level view of it.
Luffy's character has a habit of forcing everyone around him to confront themselves and chase dreams that they initially thought were too improbable to chase.
In Ace's case, he did not know if he deserved to be born. If he deserved to live. He was the son of Gold D. Roger, a man hated by all those he came across. But that was not what defined him in the end. What defined him was who he wanted to be.
Luffy lives the way he wants, regardless of his connections, prophecies and bloodline. 'Do i deserve it?' is irrelevant. 'Do I want it?' rings true. Ace starts to imitate that. Because it does matter whether you deserve it. It mayters whether you want it and are willing to chase it.
