Killua Zoldyck is the third son of Silva and Kikyo Zoldyck, making him the heir of the Zoldyck Family until he decides to run away from home and become a Hunter. He is one of the fastest-minded characters in the series. When someone praises him, especially Gon, he is easily embarrassed. As we can see here, he gets easily irritated if somebody disturbs him like in fanart Hunter x Hunter Killua Zoldyck Disturbed Sticker.