It's seems the saintess is reincarnated and she's trying to end with all of them to save the world or something. I think it's some game setup to get the good ending.
'Summoned from another world' is how she's introduced. It's not a theory that she has alternative motives
It's seems the saintess is reincarnated and she's trying to end with all of them to save the world or something. I think it's some game setup to get the good ending.