I knew petra was suspicious and a likely cult member.
She was besties with meili after all, that was the key hint.
Melancholy power seems like dogshit though, you have to vow something out of your life to to teleport someone?
Except if her prayers to od laguna is just her vow to herself, she doesn't really need to give up anything but punishes herself whenever she has to use this evil power.
I am looking forward to the flashback though and maybe more elsa, maybe capella or pandora too.