User blog comment:Martialmaniac/Zoldyck power ranking/@comment-10528819-20150616191559/@comment-5780397-20150616232156

Though we don't know for sure, I think that Silva is weaker than Zeno, perhaps due to him not being as skilled in Nen as his father. Rather than as a secret card, Zeno left him to find an opening to kill Chrollo swift and sure. We don't know the details, but Silva failed to kill the Phantom Troupe leader in the past, and he was weaker than when he fought Chrollo. However, as I said, it is merely speculation, and the difference in strength between Zeno and Silva can't be that big anyway.

As for Killua and Kalluto, Killua took out several Chimera Ants without using his aura, but Kalluto did so just because he likes to overkill his opponents; on the other hand, Killua is easily stronger than some PT members now, while Kalluto considered himself to be weaker than even Shizuku and Shalnark (though his Nen potential, as I said, might be the greatest seen n any human character in the series). I'd like him to fight Gon for Killua's love, in the future.