User blog comment:Jojo-a-gogo/ What would your nen ability be?/@comment-25377405-20141224081052/@comment-25814498-20141224212150

Insta-kills with nen are impossible because it exceeds human limits, especially if you're saying that it will be an insta-kill regardless of the targets defence, because it would basically require an infinite amount of nen, which is impossible if you're not alluka or someone else. Also, if the result in breaking your vow is only that you will be unable to use your ability for three years, that will not be a very large multiplier at all, after all, for kurapika or Chrollo to use their ability's, Chrollo had to make at least 5 conditions/vows just to steal someone's hatsu, another 5 to use it, and a final two to switch between them, and for kurapika, he had to put his life on the line and use his pure and unwavering hatred to make his nen so powerful. So if you're just saying that you're having three fairly mediocre vows and the consequence for breaking them is just that you can't use the ability for 3 years(because from what you're saying you can still use other forms of nen), that doesn't even come close to achieving this impossible goal.