Netero is at first characterized as an energetic, playful to the point of being mischievous, and at times seemingly absent minded elder. Although he seems to put on a facade of authority when called to intervene as the chairman of the Hunters Association, he is actually extravagant to the point of being sometimes called slightly insane. There were clear discrepancies between his words and his thoughts during the 287th Hunter Exam. However, he is a true martial artist who is nothing but earnest during fights. He enjoys challenges and is thrilled by the prospect of a formidable enemy. This strange passion affects the way in which he governs the Hunters Association, frequently testing the physical limits of those attempting to become Hunters. Biscuit Krueger even calls Netero a "twisted individual," as he often enjoys giving Hunters he trusts impossible assignments, sometimes with deadlines of only a few months, that should take years to complete. Netero has dedicated his life to the martial arts and prayer, intended as a form of appreciation. He displays a great deal of pride when it comes to his own abilities and has no respect for the weak. However, he is not arrogant, as he presented the possibility of Gon threatening him without saying the boy would stand no chance against him. His goal in life is to find a worthy adversary against whom he can fight with his all. His strength of mind is beyond unwavering, and he did not hesitate a second to end his own life in a last attempt to kill Meruem. The circumstances in which Netero became a Hunter and learned Nen are unknown. His proficiency was such that it earned him the title of most powerful Nen user in the world. At some point in his life, he fought Maha Zoldyck, and was the only one until then to live to tell the tale.
Netero was trained in the martial arts and, at the age of 46, he went to train in the mountains. During his time there he showed his gratitude to the martial arts and would do a set of ten thousand punches and prayers daily. On the first day of his training, it took him over eighteen hours to complete ten thousand punches. After completion of the ritual, he would collapse from exhaustion and fall into a deep sleep, only to awaken and repeat the ten thousand punches the next day. This would become Netero's daily routine for the next two years. One day after that time had passed, he realized that although he had completed his ten thousand punches, the sun had not yet set. Three years later, at the age of fifty, Netero had become capable of doing the ritual in under an hour. As a result, he spent the extra time in prayer, a development that led him to enlightenment. Some time later, Netero descended from the mountain, returning to the dojo he had begun his training in, and demonstrated his new strength. His time on the mountain had allowed him the ability to strike faster than the speed of sound, to the astonishment and amazement of his onlookers. Among his audience was the Grand Master of the dojo, who was moved to tears by the raw power and grace brought about by Netero's training. The man broke down at Netero's feet, begging to be trained, and offering the title of Grand Master in his stead. Netero accepted, under the lighthearted condition that he would be brought some food first. The Shingen-ryū school of kung fu was thus born. After becoming a Hunter, Netero joined the Seirin Group. Together with two friend of his, Zzigg Zoldyck and Linne Hors-d'oeuvre, he took part in an unofficial, unrecorded expedition to the Dark Continent and returned alive. However, the experience left him unsatisfied, as he wished for a strength that would allow him to triumph against his opponents, while there was no victory in the Dark Continent, only survival. After his son Beyond, whose existence he kept secret, embarked on a similar expedition, Isaac ordered him to never venture in the Dark Continent again.
