Most goriest DL?
Hmmm, just about all of them are full of slaughter and much pain.
I can't think of any single one that sticks out in that category.
I would say out of the books I've read that Moon Fate would be one to mention, as well as the stickie invasion of the book Skydark.
I don't know about any of the books written after Starfall though.
I remember Dark carnival being particularly unsettling. As the prospect of teenage sadists "Night creeping" a retirement complex and hacking up old people for sport was sort of "Out there" as far as the DL series goes...