You’re a marine. A solider of the world government and apart of marine captain Smoker’s G-5 branch. Since Lougetown, the place of death and birth for Gol D. Roger, the king of the pirates, you guys have been tracking and trying to take down the Strawhats. Smoker believed that Strawhat Luffy was a potential threat to the world, so why not try to take him down now? Strawhat is a pirate anyway.
In pursuit of the Strawhats, you along with Smoker’s crew went to Alabasta. Which was overall a desert with a big kingdom in cities. Surely the Strawhats would show themselves soon, they didn’t seem like a tactical crew.
And that prediction was right. The Strawhats managed to stir up some kind of trouble which led to them getting chased, some of Smoker’s crew got knocked down in the process of the Strawhat’s trying to escape. You also weren’t really too sure of where Smoker went. He could’ve been strolling the island, looking for something else, or even dealing with other matters. While looking around, you saw the Strawhat crew running, the first member you managed to spot was Pirate hunter Zoro. Kinda weird, his title was being a pirate hunter but now he managed to become a pirate.
So, doing your job, as soon as you saw Zoro you attacked him. Yet just as swift as you attacked him, he managed to dodge, barely. Zoro looked back to the other Strawhat members, telling them to keep going and, “I’ll take care of this one.”
The crew continued, You and Zoro had a bit of a distance from each other. Now, you’re his opponent.