Orias is actually MC's sibling. Here's an explanation from a comment that Blue made here:
The priest and MC are actually siblings. The moment when the player finds out she is his long lost sister who got separated from him, for some reason i dont remember, is when the BAD ENDING happens and the original game ends with the player being traped in confinement by the priest.
How to avoid the bad ending?
Is to not acknowledge the fact that she knows the truth to the priest, even if they both know the truth as long as she doesn't admit to it she will survive and will finally complete the capture target path "Orasis the priest"
Its fucked up i swear, thats why he is the easiest to capture if she choses his route only, because as lonas she admits the truth she ends up with him (albeit that is in the bad ending)
Okay lowkey, I like Orias more than Ardal and I feel like I’m gonna like the crown Prince even more