Many fans have wondered why Killua was chosen as the next successor after their father, Silva. Illumi is an emotionless and ruthless killing machine who enjoys the craft. Killua, on the other hand, doesn't even want to become an assassin.  Although there is no official reasoning for this, many fans have speculated that this of Killua's white hair and all the previous successors who also had white hair. Fans believe that because of this, Killua has more significant potential than Illumi.