Review:
MC accidentally bonds with a symbiotic spirit (called a Dark One). Initially he tries to keep his new powers under wraps and live a quiet life but when he avenges a SA attempt against his friend, he unintentionally gets drawn into both Dark One and Companion politics. (Companions are the people who are bonded to Dark Ones.) These political spheres are well-realized, with various factions and powerful individuals and no clear "good guys" or "bad guys". Main character's motivations throughout are largely to survive and protect his loved ones, but to do that he has to do some fairly aggressive things at times.
Does a good job of making you care about the characters and of presenting decent stakes (things don't always go right for our protagonists all of the time). Primarily caters to a harem/poly romantic approach (and purely hetero), but doesn't make all of the LIs feel like they're just there to check boxes off our MC's collection - they feel like they have their own lives that don't revolve purely around him. The only exception to this is his Dark One, whose life does revolve around him, but that's because she's literally bonded into his soul. Even then she has her own wants and needs that don't always align perfectly with his. Additionally, all of the LIs feel very distinct, in their personalities, their capabilities and their sexual preferences.
As a con, it's worth noting that this game is very kinetic - there aren't many choices and those that are there don't change the story much at all.
Overall, if you want a fantasy AVN that focuses on intrigue and action with a gothic/horror aesthetic, while still having decent romance/sex, I don't know of a better option. At least not if you're okay with your choices not really mattering.