At the age of 15, Hisoka was found by a traveling circus after some incident from which he came out dying. in the circus, he learned the art of aura - nen(bungeegum)he was a gifted student, for which he was feared, he challenged the director of the circus to a duel and won. then he continued to wander the world in search of a worthy opponent in order to satisfy his desires in battle. he then becomes the main antagonist in the Killua and Gon story. he doesn't have a knife 