I don't think he just doesn't want his secrets revealed, it's all a game for him, what he wants is the thrill of it, and to see his prey panick before him. He seems to be killing for pleasure in the first place, and he probably knew MC wasn't blind from the very begining
Maybe he knows that the people that he killed were lying to him in some way and he tested them to see how long they could keep their lies, also he hasn't kill anyone related to him, he kidnapped his boyfriend but that's it, his friend fell from the post by accident after answering the phone, I don't know...
I fell likebhe gave us a hint in the previous chapters when he talks about his books...
But well if the Mc take action now he would admit that he was lying and I don't think he would be able to carry his boyfriend while running away
May i fckin know what the blonde guy motive actually is? He kill all the people realted to mr blind and even play hide n seek with him too. Like, he could just kill him rite there is he dont want his secrets revealed