None other than the Chairman of the Hunter Committee, and the final authority over the entirety of the Hunter Exam. He has enough administrative power to grant anyone the Hunter's license if he decides to do so, and enough combat power to playfully avoid attacks of the main heroes single-handedly when they challenge him. All examiners, even the most despotic ones, obey his orders without talking back.
He was said to be the strongest Nen user in the world 50 years ago, but he comments that he is already past his prime at his current age and that his subordinates might be stronger than him now (yet his direct subordinates disagree). Netero is also revealed to be older than Zeno Zaoldyeck (Killua's Grandfather), who is said to be 67 years of age. At one point, Zeno says that when he was still a young boy, Netero was not only already old, but he is the only person alive who has fought with Maha (Zeno's) grandfather. Various stated times would put Netero over the three digit mark.He is able to use attacks faster than the speed of sound. His ability is known as 'Hyakushiki Kannon', or the '100-type Guanyin Bodhisattva'. This utilizes nen to make the attacks seem as if they had come from another side and or dimension, simply because they move so fast.
In the Chimera Ant Arc, he is also shown fighting chimera ants and is heading towards the destined fight with the King. His assistants Morau and Novu note that he was the strongest Nen user 50 years ago, and show great respect for his abilities.
He dies during the battle between himself and Meruem, sacrificing himself to set off a bomb in attempt to kill the king.