|"The State of Yi is now under the full protection of my army."|
|— Kuvira to the citizens of Yi.|
The annexation of the State of Yi was one of the final events of the formation of the Earth Empire. It took place in the area controlled by the city state of Yi and ended with the annexation of the constituent state.
After three years of conquering other parts of the Earth Kingdom, Kuvira's army set its sight for one of their final objections, the State of Yi. Kuvira arrived in Yi with her army, prompting the governor to ask what she was doing there. At her request, he went aboard her train to have a private conversation. Despite the imminent risk of collapse, the governor refused to sign Kuvira's offer, in which she would receive access to all of Yi's resources, namely its rich ore supply, in return for complete protection. He ordered her to leave his state and angrily left the train after being intimidated by the army commander.
His actions were in vain, however, as all of the supplies had run out, and the Air Nation representatives, Kai and Opal, were unsuccessful in bringing new supplies into the encircled city, as their collection had been stolen by one of the bandit groups that circled the skies. With his people at the brink of starvation, the governor was forced to hand power into Kuvira's hands and pledge loyalty to her. As the treaty was signed, Kuvira brought tons of supplies and several mecha suits into the provincial capital, with the objective of keeping the city and the rest of the province safe.