Is this from the latest build from Patreon? I'm on the Steam build, so yeah.The Winter City dungeon has a alternate corrupt route which takes place at the end of the dungeon.
If you've let Kas fuck your PC everytime you've interacted with her you can avoid fighting her and instead side with her. There's actually quite a lot of writing in the scenes so you can probably expect more corrupt paths in dungeons in future updates.
As for the characters im not 100% sure but I believe you will be able to corrupt some of them. If I remember correctly you can already corrupt Case.