Mm, that does make some sense. A creature that's able to kill so efficiently will most likely have a high body count. Those body counts have souls that have been killed prematurely, and will hold grudges against the world, but are trapped here because their bodies are probably never recovered.

And in turn, the miasma created by those forgotten will act against other humans as well, trying to lure them into the house.

[ he stops cleaning for a moment in order to look ahead and consider that scenario. after a short silence, he sighs, and resumes cleaning. ]

Well, that's basically just a guess right now. I'd wonder if it's possible to ask one of those other Vessels, but if Todd wasn't so willing to talk, then I feel that whatever comes next won't either.