6 Stronger: Meruem
Meruem was able to defeat Netero in a fight without any complications, which just goes to show that he's unbeatable. ... Strong as Silva Zoldyck is, there's no doubt that he's weaker than Meruem.
Can Silva kill Meruem?
Silva can defeat Mereum all by himself. He's like a more experienced Adult Gon. Zeno saw mereum and the royal guards and didn't bother to intervene to help killua. Same with silva.
Who in HXH can beat Meruem?
6 Hisoka Morow — he managed to not instantly die when Chrollo's Sun & Moon detonated, meaning that he can take a serious beating. Of course, Hisoka has enough power to handle Meruem, and where he lacks aura, he resorts to trickery, strategy, and the benefit of unpredictability.
