Oll Persson is being hunted by Chaos while time traveling

"This is Terra, before the rise of man. The things that attacked them are things that might one day evolve into men.
Except these, these corpses floating face down in the green soup, show how early the taint of the warp touched man’s home world."
-Unmarked, short story in Mark of Calth and the Dan Abnett short story collection titled Lord of the Dark Millennium