Does Bly Manor have (asking about the presence/lack of a plot element)in it?child murder/death
Well that's a bit of a difficult question to answer without spoiling too much.
I will say that there is one non-malicious child death, which you don't really see, and a sort of child death.
I watched Hulu's Book of Blood over the weekend. It was absolute trash and I want to find Brannon Braga and punch them for churning out this drek.