This all happened because the Goddess has this great love for soap operas and some of her characters tried to leave the play.
Hell, I bet the Goddess only used her because using another person in the same world will only lead to more characters trying to escape from the roles the Goddess set for them in this play.
So the horrible bitch killed and grabbed a soul from another world to take her place.
This is such a fucked up tale.
Also this doesn't explain why the she swapped bodies. Like sure, she knew about the goddess and the defined role crap... but is that really all?
The way this girl moved made me think that both she and the MC was transmigrated to their world. Because she knew too much on how things were supposed to go. I'm thinking she reincarnated a bunch of times... this crazy goddesses is replaying the drama so many times, the characters tried to jump ship. That would explain why the crazy catholic priests is so deranged.