Kinda echoing the above but I really enjoy the submissive routes you've set up for Catherine.
For me, being dominant in games like this usually falls a little flat outside of simulation styles games in the way I prefer things to be presented and explored. That having been said, this game really does nail the submissive fantasy of the main character in some really key aspects.
Evelyn's route is super hot in the way she's seducing Catherine, the initial scene where Catherine is made to give up her slave and place herself below them was incredibly arousing to me but I'm a huge fan of domination loss / switches like that. Phenomenally well written.
There's also a few scenes sprinkled in about Catherine missing Evelyn or the guessing game that Evelyn has played with her. Hell, the Symbiote scene's where it decides that it's going to be the master or giving control of it over to Evelyn was also incredibly awesome to read.
The one thing I'd like however is if there were some more byplay between Evelyn and her 'Masters' in submissive routes. The scene with the Dwarf, the scene of the Symbiote and the small scene where Catherine mentally reviews how shes feeling with Evelyn deciding to ignore her some.
Honestly, I think something that would be super awesome is inviting other people into the room to display Catherine as a slave to. That's surprisingly erotic to me. The idea of Catherine being made to serve Jeanne as she and Evelyn are discussing something would be cool.
For all I've loved Evelyn's route however, I think it's start is incredibly abrupt in some ways.
I for one would've really thought Evelyn would've played it a bit slower given her immortal nature and seduced Catherine in a way where she never had to really 'question' her obedience. But I prefer slow corruption and given the way this game updates, I totally get that it's entirely too much work to go and backdate that kinda thing when you're still building the rest of it.
But yes, all this to say excellent game and awesome story. Can't wait for more.