You or the CPU need to destroy the Meimai Knights and have completed the forced mission "Retrieve Rare Minerals" this mission will be the only available after destroying the first kingdom.
Too recute Kiratt you need to complete the mission called "Retrieve the Baubles" or http://translate.google.com/#en/ko/%22Retrieve%20the%20Baubl...
Kiratt is a bit weak compered to the enemy's here so she will need healing and constant guarding as she tend to go all in on groups of enemy`s. She has weak attacks and a small health bar so keep her safe. If she retreats the mission ends. to complete the mission you need to get to the chest with all the enemy's in the opsite corner of you`re starting point. it`s not recommend to open the other chests since this spawns another grope of foes wright on top of you with 2 turns before you get you`re first turn. More often you end up loosing a important charter like Dragan. The mission ends when you open the chest. Kiratt will join you after this.