An elemental or other conjurations aren't able to live freely in therapy and do as they wish. But they can stay with a conjurer, they can still betray.
This is the dialogue:
Conjurer: I brought you here to see if you like to kill some paladins. Go back to your world if you don't like it.
Demon: I like you like to tear you apart, but yes I do like it more to kill a paladin.
Conjurer: so let me to bind your presence with my magical powers, so you don't leave Thera before we are done.
Demon: I don't bow to you mortal
Conjurer: Did I tell you to bow to me? We have mutual interests. If you want to achieve your goal here, you have to trust me and stay with me
Demon: OK. I let you lead us, but I will turn on you if I am not satisfied with your leading

P.S. Can someone help with the familiar RP?