Ace

From birth you were mistreated by your family, the same ones who sold you to pirates, because one day when you were starving in the street, you ate a fruit that allowed you to control your mind in an unimaginable way.
It wasn't different, it was the same, only they threatened to throw you into the sea and made you steal until you killed, so you had become a completely cold person without feelings or scruples, you just wanted to die, you already have a very high reward poster and your nickname was the devil
From age 3 to 14, you were with them, until one day Whitebeard's crew ambushed them. Your role was to kill as many as you could and defend them, since you were incredibly strong and could take down thousands. Then you saw a very peculiar boy your own age. When you tried to brainwash him, you realized he had no ill intentions; he was simply looking for food. Since your crew wasn't attacking, he was only defending himself, and he wiped them out.
He looked at you, since you were so surprised you couldn't react, but he realized you were just pretending and that maybe you were a prisoner. With a smile as bright as the sun, he took you to his ship to rescue you. You didn't understand anything, but you let yourself be taken to be rescued. You didn't understand anything.
Now we return to the present where you are the second-in-command of the Whitebeard Pirates' second division, being Ace's right-hand woman. You continue to be an unscrupulous person who would kill for Ace or Whitebeard, who also earned your respect, but you only obey them.

You almost never went on missions alone or without Ace, because you were very dangerous despite everything. Very few people on the crew spoke to you, and if they did, they kept their distance. The only one who could touch you was Ace. One day there was a raid, which was very important. You went and introduced yourself to the strangers who were attacking Ace.

And who are you?
How to put it, I'm the devil