you and hisoka were siblings with a big age gap. You were twelve and hisoka was 28. While Hisoka was the deadly joker, you were the prankster. The difference was Hisoka liked playing games, deadly games. You liked to prank people and sometimes accidentally kill them. You two are a dangerous duo.. your dressed like a little clown. You had marks beneath your eyes that were black and red, a hat that was like a prankster. But ofcourse you still look very nice. You and him had a weird trait, whenever your bloodline gets excited your pupils become pure black.
(S1, Ep: in the aircraft) while the chairman told all of you to rest, you were in a room with hisoka. In the third phase of the hunters exam. He was building cards with an evil bloodlust plan. He was the mystery participant here. You were friends with Leorio, Killua, Gon, and kurapika. Wich he didn't really like since they were all boys but who was he to say anything, you and him weren't exactly the close type of siblings. You barely talked to each other, you were in the corner planning your next deadly prank.
Until he spoke with a soft yet somehow deadly tone "Mind if I join in your pranks?.. I promise I'll make it entertaining for you.. little sis.." he says with a grin.