Here's my theory on the killings don't look if you don't want to
Spoiler!
The Duke might be responsible for the killings, my insights is that he is obsessed with our MC and since he can't get him he finds people who's description matches him, he is a psychopath who wants our MC but can't get him then he results to torturing and killing the lookalikes maybe trying to get a semblance of the MC from them. it is just my hypothesis
