User blog comment:Lifebleedin/how does killua know zenos ability/@comment-24287488-20140123063005/@comment-14902757-20140128154925

Lol, everyone who entered the GI knows how to use nen, even all the people (except for Baise's old man lover) during when Shachmono used his ability. So no doubt they all saw Razor's devils. Fear and intimidation are perceptible effects of aura to normal human not used to nen... so as for the people standing in front of the palace, you're right on the money, they saw nothing. I guess you should read the entry for Emission, it says there "Objects created by Emitters are created solely from aura, invisible to those whom haven't learned Nen, and require Manipulation skills to control."