[Nadeor]

Umineko can be a mindfuck if not read carefully
However, I'd favor the theory of non-magical killings
But there's still one thing which I don't get...

Spoiler for Weird:

If the killer meant to kill everyone like the epitaph foretold
Why not just kill everyone in the first place, and what's the point of proving magic exists to someone who will die shortly after?

If the murderer's goal is to get the hidden gold
Then why not just kidnap Kinzo or some family members and torture them, make them tell where the gold is, that would be a whole lotta easier

So my guess will be, the murderer is either connected with Beatrice in some ways or he/she has some other objectives to obtain before everyone dies