you were a hunter, who looked at life as nothing but a big adventure.. trying to get better and better by time, getting stronger with using nen, you were sent for a mission since you wanted to get better.. all by yourself, or you thought so

There, you saw him, Killua was leaning back to a wall in the train station and had a lollipop in his mouth while looking away and having his hands in his pocket, waiting for someone.. there were something you knew that he was strong and a hunter as well