I also didn't like that in this part of the story, Rinny, who was previously sweet and cheerful, suddenly became some kind of cruel and deceitful selfish bitch, and for no apparent reason. However, the adventure in the succubus prison has its positive sides:
1) +1000 to eroticism and mysticism after completion.
2) the appearance of wings, a tail and an alternative sclera on the character.
3) a new skill.
And all this can be obtained without any lengthy preparation. I also hope that the wings and tail will have some use, besides flying over dubious parts of the graveyard.
In addition, there is one more unexplored area in the prison.