Isaac Netero

Netero is an extremely powerful practitioner of Nen, claiming the title of the most powerful Nen user fifty years prior to the series. He has control over at least three Nen categories: first, his natural category, Enhancement, which, in conjunction with his astounding martial skills and strong body, make him a dreadful melee fighter; then Emission, which he uses to activate his strongest attack; finally, he employs Manipulation to make the Nen statue mimic his movements. It is said that, because of the extremely quiet flow of his aura, one cannot read his next move. While his amount of aura is immense, impressing seasoned Hunters like Morel, who commented it felt like being pierced by needles, Colt stated it is incomparable to that of the three Royal Guards; still, he managed to dispose of Neferpitou in an instant and injure Meruem himself, demonstrating his superior mastery over the art.  Netero has also been seen to be a master of "the other Nen" as well. As it turns out, his hostile "Ren"(commonly known as blood-lust) was so powerful that it made Meruem, considered by most to be the most powerful character in the series, feel fear for the fist time. A much milder version was also felt when he saw Gon and Killua on the airship going to the second phase of the hunter exam sight. There, he shot his blood lust at them in a fraction of a second before disappearing into another corridor. This show of "Ren" was strong enough to out them on edge for a short while and make them wary of his presence, completely changing the atmosphere.