Due to the effects of the Harmony Restoration Movement, Yu Dao started the process of decolonization, and Master Kunyo was forced to give up his property and transfer it to Earth Kingdom ownership. The building in which his school was located was confiscated and sold to Toph Beifong, who transformed it into the Beifong Metalbending Academy. However, after Fire LordZuko withdrew his support for the movement, Kunyo returned with his three students to reclaim his property. When he arrived back at the building, only Ho Tun, Penga, and The Dark One were present, and he easily managed to drive them out of the school. However, right after he had reclaimed ownership of the building, Toph returned and proved to be a much tougher opponent than her three students. Kunyo laughed at Toph when he found out that she was teaching metalbending, as he thought that it was impossible, a mere fantasy. However, Toph proved him wrong by metalbending one of the spears that served as wall decoration around his head. When the two sifus were about to battle for the right for the school, Sokka halted them and proposed to let their respective students fight it out instead of the masters as they would have effectively destroyed the entire building. Kunyo agreed to Sokka's "battle to the sit" proposal, as opposed to a "battle to the death", which meant that the first team of students that managed to make another student sit down was victorious, and left the school to be back for the face off in three days, but not before giving them the "Kunyo salute", an acrobatic move demonstrating his students' abilities.
On the day of the battle, he returned to the academy full of confidence; however, he had been unsuccessful in removing the bent spear from his head, which Sokka mocked him for, so he had decorated it with two flags, one sporting the firebending elemental symbol, and the other one sporting his school's symbol. He appeared to have won back his school when a hopeless Toph surrendered. However, her attempt to sit down and surrender was thwarted when her metalbending students came back to the facility trying to stop her, as Ho Tun suddenly metalbent a coin. Aggravated, and presuming this to be a "dirt people trick", Kunyo ordered his disciples to attack, but he found that their firebending was useless against the metal coins of their opponents. Nonetheless, Kunyo demanded that his disciples continue firebending, until he was knocked on his face when he was hit multiple times with several of these coins, causing him to fall sat down and lose the battle. Defeated, he walked away, supported by his students, re-allowing Toph control the academy.
Kunyo did not give up, however, and sent an official complaint about a "dirt girl" - Toph - and a "snow savage" - Sokka - taking over his school to Fire Lord Zuko. Nevertheless, his complaint was ignored, since the Fire Lord was about to fight a new war and had no time for such matters.
Master Kunyo was a hot-tempered man with an arrogant and theatrical manner. Because of his obstination, he refused to back down even when wrong, as evidenced when he decided not to remove the spear that Toph had wrapped around his head with metalbending, instead decorating it with Fire Nation banners. Proud about his Fire Nation ancestry and condition, even looking down other benders, Kunyo transmitted his thoughts to his students while training as a way of encouragement. In fact, his attitude toward other people, for example to call them "dirt people" (Earth Kingdom) or "snow savages" (Water Tribe), bordered on racism and mockery.
Though authoritative, however, he proved to be a very effective teacher, as even Sokka and Toph were impressed by the abilities of his very young students.
He usually showed a no fear attitude when confronting his opponents, and he taught his students to do so. This attitude is clearly noted when they all agreed to fight a 'match to the death' with Toph's students.