Gyro initially appears wearing a large down coat. During his flashback, Gyro is drawn as a black silhouette.
Having spent his youth in a construction camp, Gyro is both rational and productive, traits that, together with a brilliant mind and a natural charisma, allowed him to build an empire. Despite years of abuse from his father, Gyro only lost his humanity following the realization that no one ever loved him. He thus stopped considering himself a human and started to despise the whole race. He has since become both a cruel and ruthless man. His goal became to disseminate evil throughout the world, and he still pursues it. His tenacity and pride as a former king allowed him to keep all of his human memories and break free of the Chimera Ant Queen's control, vacating her domain. His malevolence and determination are second to none and now, having been reborn as a different species is completely disconnected from the human race.
Gyro grew up in a construction camp; he learned how to mix concrete and lay bricks before he even learned how to talk. Gyro's reticent father was akin to a god to him, despite spending the days in a drunken haze while imposing strict conditions on the boy—beating him at the slightest annoyance or impulse. After returning from work, Gyro was forced to stay on the top bunk of his bed and denied access to the outside world, except for when he needed to use the communal washroom during the daytime. He was not allowed to leave his house after 9 PM. Gyro's father hammered into him the mantra, "Don't ever make trouble for anyone!"—words Gyro always treasured. Even amidst the abuse Gyro constantly suffered, the boy always respected his father and believed, he truly loved him. There were two reasons for Gyro's faith: the first one was the belief that his father took care of him after nearly dying from an illness at the age of five. The second was that his father never once told him to leave; both made Gyro proud.
However, at the age of twelve, Gyro snaps when another boy makes fun of his father. Outraged, Gyro attacked the boy and was badly beaten. Thereafter, the boy revealed that Gyro's father never took care of him when he was sick—it was the old neighbor next door instead. His father had been getting hammered, as usual. In addition, the boy told Gyro that his father said that he didn't care if Gyro lived or died. Gyro's father then walked past the two, looked the other way, and walked away from the scene. Gyro then understood that his life is insignificant to the universe as a whole: he was no one. It was this revelation, along with learning the cold-hard truth about his father and his "lesson" being a complete lie, Gyro finally snapped. Shortly afterward, Gyro took a hammer, smashed his drunken father's skull, took all of his money, and left the camp. At some point, possibly after killing his father and leaving the camp, Gyro developed the D² drug. The purpose of this drug was to spread evil and ruin the lives of others, now having come to utterly hate humanity as a whole.
Nine years later, Gyro formed NGL, which was established into a nation in another nine years. At some point in his life, Gyro met Zaiqahal. Feeling empty inside, and thus having nothing to hide, the two quickly became friends and would often argue about who between them had the worst luck. He is then killed and eaten after the Chimera Ants invade NGL and reborn as a fellow Ant. But, due to his strong will and unyielding pride as a king, Gyro retains his human memories, ignores the Queen's orders, and leaves the NGL hive.
Chimera Ant arc
While Gon and Killua were in Doli City sometime after their encounter with Neferpitou, Gyro was also in the same city, though they never meet. His location after the Chimera Ant Queen's death is unknown, but it is believed that he is trying to rebuild his empire again. During the seize on the Royal Palace of East Gorteau, both Welfin and Ikalgo realize that Gyro was their king during their previous lives. Welfin still believes that Gyro is alive and is determined to find him. Thus, following the events culminating at the national rally in East Gorteau, Welfin, Hina, and Bizeff all depart to Meteor City, where, according to Welfin, they are likely to find Gyro as he attempts to establish a new nation.
Abilities & Powers
Prior to his death, Gyro was the king of NGL as well as the kingpin of its underground world, which means his authority extended to both sides of the law. It is thus safe to assume he was the most powerful man in the country. His intelligence and skills are such that he successfully created a kingdom in eighteen years, starting as little more than an orphan child and with a paltry amount of money. After being reborn as a Chimera Ant, his strength of mind and unquenchable hatred for humanity allowed him to retain his personality and memories, which prevented the Queen from controlling him. Gyro seems to have been an incredibly charismatic individual: his subordinates were—and, in Welfin's case, are—willing to defy death for his sake or even for his honor, and Ikalgo has such faith in him that he believes his former king to be still alive somewhere.
* Gyro's stats are:
Manga and Anime Differences
Translations around the World