So this is what Grave meant by they're more similar to each other than she thinks.
It's a twist but isn't it still pretty dumb tho? That's a lot of blood and effort just to not go on a quest-type mission. Why not send a body double, another healer, just show your face to the people and skedaddle home? If they got dark magic they can also just use dark magic on the 3 fishes and make them ok with it.
To be fair I'm pretty sure current Grace is actually pretty dumb lol. Also, I'm not too sure but I think I read in the spoilers also that she has a book with the plot of the story so I guess she wanted to follow it exactly as it said but decided to go to extreme (and stupid) lenghts just to not go on the quest herself
These are spoilers about the big plotwist of the novel I think
Soooo... I went looking for some spoilers and apparently that Grace girl was the original FL (she IS the real Sellonia) but she didn't want to go on the trip to subjugate the demon king because it was a rough trip (she didn't want to sleep outside and be cold and all that) basically she was a whiny b*tch, so she and her dad (yes, the dad is in on it) sacrificed a bunch of people to perform a dark magic ritual to exchange bodies, and so it happened that a random soul from Korea was brought to Sellonia's body (our current FL) and the original FL Sellonia (now Grace) took over a poor random extra girl's body (original Grace).
And then our FL went on the trip, came back, Grace must have done something to put her in a coma and used dark magic on the 3 romantic interests. Now, Grace (original Sellonia) and her father (Sellonia's father) are again killing a bunch of people to sacrifice them to perform the ritual to regain Sellonia's original body.
Correct me if I got anything wrong :)!