

Shortly before the cessation of the Equalists, Hiroshi gave his daughter one last chance to join him, but she refused and a battle fought using mecha tanks commenced between the two at an Equalist airfield. Once Hiroshi's true aspiration became known to the general public, the reputation of the Sato family was compromised and they suffered a great loss of wealth and status, leading to Asami's arrest on Tarrlok's orders due to her father's affiliation with the Equalist movement. Grieved by this revelation, his daughter Asami defied him and joined the Avatar to put a stop to the Equalists' acts. He became one of Amon's most loyal and devoted followers, though his status as a high-ranking Equalist was not known to the public until his secret factory was discovered by Team Avatar.

Hiroshi used his surplus of resources to make numerous machines and weaponry for the Equalists, who quickly began utilizing them against benders. Hiroshi created the mecha tank to aid the Equalists' fighting efforts and eventually tried to kill his daughter with one. This tragic event was the primary factor in manifesting Hiroshi's deep hatred toward all benders, prompting him to join the Equalists to avenge her death.

Six years later, the Agni Kai Triad raided the Sato estate, resulting in Yasuko's death. He married Yasuko, a successful architect, and, in 152 AG, they had their only child, Asami. Later, his conception of automobiles for the common man made him a wealthy figure by the age of twenty-five. However, the first known member of the family is Hiroshi Sato, who was born to a poor family residing in the Dragon Flats borough in 120 AG. The family lineage originates from the first Fire Nation colonists.
