I'm a little mixed with this VN. I really like the idea of the MC's race and past, which I think is quite unique. I honestly think that you could center the entire story around this aspect, and make it more of a slice of life, and it would be really good. I also like the other main characters, their designs and personalities seem interesting and diverse. And the art is great.
I'll be honest, the "mystery" fell really flat for me. There was no build up to it all, making it feel shoehorned in. The character involved had 1 scene prior, so also no investment in them at all either. And the fallout seemed weird? The MC seemed to care about it as much as I did, more interested in boning his teacher. And there was little to no reactions from anyone else other than Kamil...
I also felt the sex aspect felt rushed and forced. You have some really good, interesting ideas for your characters... but the horniness and sex aspect felt weird and forced, especially with Brendan's route.
All in all, I think currently, your interesting and good character ideas are just clashing with the "mystery" and sex scenes, making it almost feel like I'm reading 3 different stories overlapping.