User blog comment:Jojo-a-gogo/Do you guys think that Killua will ever fight Illumi in future chapters??/@comment-2225197-20130108115254

It could be possible, or it couldn't be. First of all, they're family. Killua may have enough reason to take Illumi on a life and death match. But always remember that Killua has his Father who kept his eyes on Killua and his progress. So, to put it simply, I would say 50-50.