The Deep Norns start out as terrestrial, innocuous-looking babies and gradually metamorphose into fully amphibious elders. They come with their own metaroom, Devil's Reef, and an agent pack containing three agents: cute star-spawn plushies, a basket of muffins, and a copy of the Necronornicon. They occupy Norn Slot W.
Deep Norns are quite unique, as they don't die of old age, and have a slight resistance to heavy metals, although they are not immune to them. Although Deep Norns can eat regular food, they often prefer to eat critters such as fish.
- A Deep Norn appeared on the CCSF 2008 website wearing a Santa Claus Hat.
- The Deep Norns are inspired by Lovecraft's Deep Ones in The Shadow Over Innsmouth.
- When Deep Norns reach the adult stage of life, their eyes will remain open whilst they sleep. This is because, like fish, they have no eyelids.