Killua is usualy very cheeky, cheerful and full of mischievous ideas. He is also very smart and has a quick thinking, capable of analyzing most situations with ease and accuracy. He is very confident in his abilities. He however has a second side to him. Once he switches to this side of his, he becomes ruthless, deadly and almost bloodthirsty. But these moments are rare as he usualy keeps his cool. Despite all this, he is very loyal to his packmates and is very overprotective of them. He usualy puts others before himself even if it means him getting hurt.