The Earth Empire is a rogue military faction within the Earth Kingdom and is the main antagonist faction of The Legend of Korra Book Four. It's a nation founded and led by Kuvira that seeks to reunify the fractured and fragile Earth Kingdom under her banner while also seeking to annex the United Republic of Nations and abolish the old monarchy from before.
Origins and Foundation
In 171 A.G., the Earth Kingdom had descented into chaos and anarchy following the assassination of Queen Hou-Ting at the hands of Zaheer and the Red Lotus. With her death, the nation fell apart and anarchy spread across the land. Kuvira was trusted by world leaders and assembled an army of supporters and followers to embark on the mission to reunfiy and stabilize the Earth Kingdom. During this time, Kuvira was succesful in ending the chaos and recruited both Bolin and many anti-royalist citizens of the Earth Kingdom.
Kuvira and her army traversed the Earth Kingdom for three years and finally ended the chaos in 174 A.G. and reunited the nation with military discipline. 90% of the country was under control and stability returned to the shattered nation but, the wealth and peace soon came to an end as Kuvira's mercy ran dry and she grew to become more domineering and tyrannical, as she began enslaving the citizens of the country to maintain her armies and those of non-Earth Kingdom ethnicity were sent to re-education facilities. Eventaully, Kuvira and her armies marched on the State of Yi and forced many bandits to swear allegience towards her and join in her chaos.
Annexation of the State of Yi
Kuvira and her forces eventually marched and arrived in the Earth Kingdom state of Yi. There, the governor of Yi was displeased with the military presence in his state and even thought that bandits overran the State of Yi itself. In a private audience, Kuvira confronted the governor and demanded that he surrender and hand over Yi to her and her forces. At first, the governor was hesitant and demanded that Kuvira leave and her army withdraw stating that he had no intention of handing over Yi to Kuvira and her troops but, she wasn't accepting his answer and instead gave him a day to reconsider. Over the next day, bandits would attack and raid supply trains and cut off any form of relief and aid to the state and so, the governor said yes to Kuvira's intervention and she returned with her army.
The Earth Empire military eventually arrived into Yi and the governor surrendered and the State of Yi was handed over to Kuvira and annexed into the Earth Empire while the bandits were finally delt with and peace was restored. Kuvira and many of her followers and officers of the Earth Empire attended an award ceremony where Wu would be crowned as the new Earth King. There, Kuvira was given an award but, she took over the event and declared the establishment of the Earth Empire, the dissolution of the Earth Kingdom and the abolishment of the monarchy leaving Wu without any form of power or authority and was met with applause from her followers. She then threatened world leaders that they would suffer military counter-attacks if they responded with force.
Battle and Fall of Zaofu
The armies of the Earth Empire continued to march forward and headed towards the state of Zaofu, which was the last Earth Kingdom state left to be annexed into the empire and its territory. During their march towards Zaofu, only a few soldiers were left behind to defend the borders of the newly formed empire with two of them having captured Ikki believing her to be a spy. After finding out that she was the daughter of Tenzin, the two ended up plotting to capture her other siblings and parents believing that Kuvira would promote them. However, the two outpost soldiers bonded with Ikki and eventually began helping her locate where Korra could've been hiding out and upon releasing her, the two soldiers were ambushed and knocked unconcious from airbending attacks by Jinora and Meelo.
Upon their arrival at the home of the Metal Clan, the army had made camp at its gates and gave Zaofu 24 hours to surrender. During this time, Bolin questioned his loyalty towards Kuvira and he eventually deserted the army along with Varrick and Zhu Li via escaping in stolen mecha suits. Their escape however, did not go unoticed and Bataar Jr. ended up leading an effort to capture the three deserters resulting in a battle that ended with the three of them being captured. Bolin was sent to a rehabilitation camp, Varrick was forced to continue developing weapons for the Earth Empire and its military and Zhu Li was pardoned after she pledged her alliegence towards Kuvira.