User blog comment:First comes rock/Do you think Netero's Nen ability has any Vow & Limitation?/@comment-11187933-20131023070636

While it's possible that Netero has some sort of condition placed onto his ability, I doubt that it's the one you mentioned. If he could only use his ability against certain opponents then he wouldn't be able to train with it. For something like Kurapika's Chain Jail this isn't a problem; because landing the move automatically ends a fight, so there's no need to train it. Hyakushiki Kannon, however, is a really technical ability. With all of the different gestures and the overall size of what he's controlling, I find it hard to believe that he's only used the ability a couple times.

Going along with that though, it seems likely that the gestures would act as a condition. I don't see why else he would take the time in the middle of a fight to do hand signs that only serve to give away his next attack.

He might not even need any limitation though. On top of being 110 years old, he seems to have an obsession with training. His experience with Nen is probably much higher than anyone else's in the series. Considering that, i don't think his ability is too ridiculous.

As for what Zeno said, Netero has proven himself to be good at Emission. This would explain the attack against Pitou where he emitted a blast of aura. Also, he's an Enhancer so he can probably enhance his own body. Basic Emission, basic Enhancement, and Hyakushi Kannon would be 3 different Hatsu techniques; with Hyakushiki being the strongest.

Also, the Zero Hand condition (if it can be called that) is pretty obvious. He has to launch all of his aura out at once.