User blog comment:Silva92/Killua's Nen/@comment-7388020-20130721235136

Read the comments, I'm kind of thinking Silva never wanted to teach Killua Nen because he didn't want him running away from home. Though he did end up running away anyway, but only from the father's approval. If he had taught Killua Nen was he was 5 or so, Killua might have left and never come back, and the father and mother never would have wanted that.