Story appears to be an allegory about social stigma and extreme alignments. The chaotic and true to their desires demons are 'evil' while the orderly and controlling humans are 'good'. The 'good' humans have shown themselves to be harsh and cruel in her first 2 lives.
The church has zero care for her and are eager to kill her through sacrifice once she performs her duties. They have no regard for her as a person and deny her basic pleasures and once her role is done they even plan to deny her life, sacrifing her. They didn't help her in life 1 and they actively killed her in life 2. So now she is exploring the demons in life 3 and trying to understand what they're truly about beyound what the church has indoctrinated. And already we are seeing a lot of symbolism about balance.
Ngl I sorta don't understand