User blog comment:Abdulrahman93/About Silva's nen type/@comment-37.104.9.151-20120829040314/@comment-5314364-20120830050301

Think about it.

He's not simple minded(enhancer) because it shows that he's tactical in battle

He's not impatient (emitter) considering that he is waiting for killua to come back to the family business

He definitely not high strung (conjuror).He's a calm and collected assassin.

He's yet to show any charismactic traits(specialist).

The only other thing that seems to be a possible choice is manipulator which I highly doubt considering that his attack leans towards transmutation as oppose to manipulation nen.