User blog comment:Pigzillion/How come Killua learnt Nen so late?/@comment-26870630-20150809014335

Unfortunately, this appears to be a plote hole. Killua says he didn't even know nen existed before the Heaven Arena arc. However he had seen nen before that.

1) He recognized Zeno's Dragon Dive during the Chimera ant arc, even though he did not see it between the Heaven Arena arc and that point. That means he saw it before the show took place.

2) He knew about Alluka's wish granting abitlity.

Furthermore, Kalluto knew Nen at the age of 10. In fact he was extremely skilled, meaning he had been studying it for at least several months, if not years. If Killua was supposed to be the prodigy of the family, why did he not even know of nen's existance at the age of 12 when Kalluto knew it at such a young age?