can someone tell me whats the order of the game? like what do i play first? Khemia, Interea or Adastra? i want to play them by order so i can understand the story much better :)
You indeed have to play Adastra since Khemia's a sequel.
However, it doesn't matter what game you play after Adastra. Interea's a short story focusing on one point of Adastra (in the game, the events happening in Interea are summed up in a few lines). Khemia's a sequel happening a couple years after Adastra! ^^