She wants to make her own realm and sees Atia as the main obstacle. So she wants to kill her no matter the number of people who die along the way.
At least that is my reading of the game's story.
We will see what the next update will bring, there are many secrets in the game: Atia-Naamah, Atia-Onique, Atia-angel child, on the light and middle path Vant and his artifact, maybe there is something between Atia-Envy, Mara and Deva, she also did not specify what happened , each succubus has its own specialization (leader, bodyguard, sleuth , fighter, mage),
let's not forget that Atia plans years ahead, it's safe to say that Atia wants Thalna to become strong, but why?? Many questions, time will tell.

