During the battle for Republic City, Tenzin sent a message to General Iroh requesting the support of the United Forces. The General accepted the request for help, wishing to reclaim Republic City from the Equalists alongside AvatarKorra, and led his fleet of battleships to the city.
Once Iroh and his fleet reached the shores of Republic City, he was surprised at the apparent silence and the fact that there were no Equalists awaiting them on shore despite their knowing about his arrival. However, the general and his fleet were quickly overwhelmed by a series of naval mines and the new high-speed aircraft fielded by the Equalists. At one point, Iroh himself attacked from the helm of his ship, launching fire blasts at the enemy biplanes; he managed to destroy several until he struck a bomb in midair with his firebending. The resulting explosion catapulted the General overboard and into the ocean, where he was later rescued by Avatar Korra.
Taking Republic City back
With his fleet destroyed, Iroh and Team Avatar hid in the sewers of Republic City. While he had his wounds healed by the Avatar, he and the team planned to take out the Equalist airfield. To prevent the second fleet from being destroyed as well, Iroh sent a message to CommanderBumi via former telegraph operator Gommu, telling him to wait with his fleet at Red Sand Island until the airfield was taken out. Korra decided to stay in Republic City to face Amon, although Iroh did not approve of the idea. Korra insisted and Mako decided to stay with her. The General allowed her to stay, stating that his grandfather would have trusted the Avatar's instinct and he should as well.
When Iroh, Asami, and Bolin reached the airfield, despite Asami's confusion over the airfield being surrounded by a fence with no wires, they proceeded anyway and were electroshocked by an electric fence that surrounded the complex. They were caught and subsequently imprisoned, where the group was confronted by Hiroshi Sato, who told them that he had intercepted General Iroh's wire to Bumi and knew exactly where his fleet was hiding. Seeking a means of escaping, the General asked Bolin if he was a metalbender, but he answered that he was not, much to Iroh's disappointment. Naga, however, arrived on the scene shortly afterward and broke the three out of their cell, allowing them to head toward the airstrips.
After escaping, Iroh pursued a taxiing biplane down a runway. By utilizing his firebending in a manner similar to rocket propulsion, he successfully boarded the plane as it took off, hijacked it, and forced the pilot to bail out.
Once inside, Iroh struggled to control the machine; eventually, however, the general gained control of the aircraft and used it to intercept a squadron of five aircraft flying over Republic City. He was able to destroy two airplanes during his initial attack with lightning. Following this, his own biplane was destroyed when an Equalist bola jammed the propellers.
Once again utilizing the rocket propulsion technique, Iroh boarded a second plane, fatally damaging another plane with his firebending before commandeering the biplane. During the fight, Iroh's biplane was damaged by the last aircraft which had dropped a bomb on the tail of his aircraft. As the other biplane prepared to continue the bombing, Iroh used his firebending to detonate the remaining bombs in the attacking plane's bomb bay.
Despite his success, Iroh's airplane was damaged to the extent that it could no longer remain airborne. He unsuccessfully attempted to steer the plane away from Aang Memorial Island and had to bail out, grabbing onto the Equalist banner hanging from the statue of Aang to save himself. Iroh watched as his biplane crashed into the statue's face, causing the giant replica of Amon's mask to fall off into the water. Iroh subsequently thanked Aang for watching over him.
Six months after the end of the Anti-bending Revolution, Avatar Korra requested Iroh's help once again to aid the southerners against the Northern Water Tribe. Aware that helping Korra would mean going against PresidentRaiko, Iroh informed her nonetheless that he was willing to help, musing that he could mask it as a routine training session; if he were to take his fleet south and happened to encounter hostile Northern troops, he would have to defend himself. However, in the middle of their meeting, President Raiko boarded the ship, commanding Iroh to remain at the harbor unless he received direct orders from the President stating otherwise. Raiko made it clear that if Iroh were to disobey those orders, he was to be court-martialed. Unable to help Korra out himself, he suggested that she travel to the Fire Nation to talk to his mother, the Fire Lord, as she and his grandfather had always been good friends with the Avatar and the Southern Water Tribe.
During the Harmonic Convergence, Iroh was ordered by President Raiko to protect Republic City. Upon seeing a large incarnate of Unalaq and Vaatu merged, the general ordered his troops to attack him. However, their attempts proved to be futile as the Dark Avatar easily neutralized their attacks, and waterbent the battleships away with a large wave.
After Kuviratook control of the Earth Kingdom and planned to attack Republic City, General Iroh erected defensive barriers around the city. While eleven of his battleships were stationed at Yue Bay, he brought his ground troops to a clearing on the outskirts of the metropolis; having deployed five battalions of foot soldiers, aided by thirty-five mecha tanks in total, he awaited the arrival of Kuvira's army.
A week after their preparations began, General Iroh received a call from Lin Beifong, who alerted him that their previous assumption of Kuvira's arrival still being a week away was wrong and that the attack was happening that day. Avatar Korra joined him at the front line, though Iroh was shocked to witness the arrival of the enormous mecha suit that destroyed his fleet in Yue Bay in a matter of seconds with the spirit energy cannon it carried. When Kuvira aimed her cannon at his infantry, Iroh called President Raiko to confirm if he had the order to engage. His request was denied, however, as the president surrendered the city. Angered about hearing Kuvira demand the surrender of the United Forces and the Avatar as well, he told Korra to retreat to the city before she was spotted by Kuvira and figure out a way to destroy the spirit energy cannon.
Iroh is a disciplined and determined man, unwilling to give up without a fight. Like his namesake, he is very cautious and methodical in his approach during battle. Furthermore, he has shown great bravery on the field, willing to risk his life to aid his allies without hesitation. Despite his senior rank among the United Forces and his status as a member of the Fire Nation Royal Family, Iroh is a humble man, openly showing his sincere gratitude for other people's assistance. Likewise, Iroh is very loyal to his friends, willing to do whatever is in his power to help so long as it does not outright defy authority.
Iroh has demonstrated great skill in firebending, as shown by his ability to generate lightning and the use of firebending to propel himself through the air with great speed and accuracy, fast enough to catch up with a speeding airplane. He also effectively took down numerous airborne planes with only his bending. Furthermore, he is a quick learner, as he was able to figure out how to pilot an Equalist biplane despite his lack of experience with them.
In the Hebrew dub, Iroh is also voiced by the same actor who previously voiced Zuko in Books Two and Three of the original series.
Iroh is the fourth of seven people to be seen using firebending to propel themselves into the air, and the first person to do so in The Legend of Korra; the others were Azula, Jeong Jeong, Ozai, Mako, Wan, and Korra.
Having destroyed many aircraft, Iroh would be considered a flying ace, that is, a pilot that shoots down five or more enemy aircraft. He also earned it in a single day without any prior experience or training, an incredible feat for a real world pilot. As such, he would be the first known flying ace in the World of Avatar.
After the initial skirmish following his arrival in Republic City, General Iroh gained a burn scar on his left arm reminiscent of his grandfather Zuko's burn scar.
The way that Iroh said that if "[his] grandfather would respect the Avatar's instinct, [he should, too]" is very similar to how Zuko would ask himself what his uncle would do.
The original Iroh and KingBumi worked together in the Order of the White Lotus, much like how Zuko's grandson Iroh and Aang's son Bumi worked together in the United Forces.