User blog:Silva92/Killua's Nen

i was thinking alot about this and i couldn't find a logical explanation about this.

why didnt silva teach killua about nen?isnt he supposed to be an assassin? wouldnt a nen abilty make his job easier?

what if one of his targets happens to be a nen user or has bodyguards who use nen. and why did he teach it to illumi and kalluto (who is younger than killua) but didnt teach it to killua, didnt he say that killua has alot of potential, this doesn't make sense to me. what do you guys think?

p.s sorry if my grammar is not well written.