Many creatures appear in The Infernal City and Lord of Souls, some new and some old.
- Annaline
- Annalines are creatures from the Sump on Umbriel that get used as an ingredient in its kitchens.
- Antelope
- Antelopes with twisted horns appear in Hircine's realm.
- Barn Owl
- Colin hears a barn owl in the Imperial City.
- Bladefish
- A type of fish found in the sump of Umbriel. When Annaïg's poison works on the city they barely react to Glim.
- Boar
- Annaïg notices a boar being prepared in the kitchens of Umbriel.
- Carrion Scorp
- Carrion scorps are creatures found in the Sump of Umbriel that are known to feed on the bodies of the dead.
- Catfish
- Catfish is used as an ingredient in the kitchens of Umbriel.
- Chest Borer
- A type of parasite found on Umbriel. Toel thinks of this when Annaïg tries to explain the concept of pregnancy.
- Cilia Tubule
The living waste disposal pipes and water filters of Umbriel. Known to have a series of sphincters. Mere-Glim sabotages them by temporarily paralyzing their sphincters.
- Coot
- Attrebus hears the calls of coots upon returning to Cyrodiil from Vile's realm, and it sounds like home to him.
- Crocodile
- Crocodiles live around Lilmoth. Annaïg believes that there is a were-crocodile around, but Mere-Glim points out that normal crocodiles could make the same tracks.
- Curlew
- Attrebus hears the calls of curlews upon returning to Cyrodiil from Vile's realm, and it sounds like home to him.
- Dash Clam
- A type of clam from the Sump on Umbriel that gets used as an ingredient in its kitchens.
- Deer
- Fruth tells Attrebus that deer are one of the creatures hunted in Ensleth Valley.
- Dreugh
- Annaïg spots some dreugh on the ground, fleeing from Umbriel.
- Elk
- Fruth tells Attrebus that elk are one of the creatures hunted in Ensleth Valley.
- Firefly
- Attrebus sees fireflies in County Bravil.
- Flounder
- Mere-Glim witnesses a fish-monger selling flounder in Lilmoth.
- Frog
- Attrebus hears frogs singing in County Bravil.
- Greem
- A creature found in Elsweyr, though nothing else is known about it. Sul tries to get himself and Attrebus out of trouble by saying that they were a mile off the main road looking for a flock of greems because Attrebus had never seen one, rather than telling the truth: that they were bringing moon sugar to Khajiit.
- Hare
- Chef Toel creates a meal course for Lord Irrel using hare.
- Hedgehog
- Hedgehogs are one of the many things used as an ingredient in the kitchens of Umbriel; in one meal they are seasoned with eucalyptus.
- Hob
- Hobs are hairless monkey-like creatures used as assistants to the chefs on Umbriel. They are long-limbed, have very long, thin, delicate fingers, a huge toothless mouth and large green eyes in a goblinesque face, and very simple language skills. Annaïg names her first Hob "Luc" and her second "Dimple".
- Horker
- Horkers are three-tusked walruses found on the island of Solstheim. In Sathil, Attrebus claims that he is a naturalist and that he wants to study creatures such as the horker, which he had seen on the nearby beach.
- Kraken Barnacle
- A type of barnacle native to the seas around Lilmoth: dark green, and the size and shape of a large shark tooth. Mere-Glim finds them growing in the sump of Umbriel.
- Lampen
- A clamlike creature from Umbriel, used as a cooking ingredient. Known to invade the cilia tubules.
- Larkin
- Ilzheven mentions a bamboo grove where larkins sang.
- Moon-adder
- A viper from Black Marsh. Its venom is fatal to most beings; Argonians, however, are resistant to it, and occasionally seek it out as an ecstasy-providing drug. Annaïg uses it when cooking.
- Muskrey
- A type of creature hunted in Ensleth Valley alongside elk and deer.
- Nickfish
- Nickfish are silver-colored fish found in the sump of Umbriel. They are a food of sessile crabs.
- Nightjar
- Attrebus hears nightjars in County Bravil. Referred to as just "jars".
- Orchid Shrimp
- A creature from the sump of Umbriel, with buttery-tasting meat. Slyr gives Annaïg a biscuit made with it, and Fhena asks Mere-Glim to bring her some for use in the kitchen she works in.
- Phosphor Worm
- A creature from the sump of Umbriel that gets used as an ingredient in its kitchens.
- Pigeon
- As Colin eats a meal on a roof, pigeons try to steal his food.
- Pogfish
- An edible type of fish. Annaïg's father has some of the salted meat at his house.
- Proform
- A featureless wormlike creature found in the sump of Umbriel. Whenever a person on Umbriel dies, the Ingenium calls a proform down to it and gives it a soul, and the proform attaches to the wall of the sump and grows into a person.
- Ripper Eel
- A type of eel found in Lilmoth; there are ones in the canal that have been trained to hunt Argonians swimming there, but a skooma smuggler avoids them by rubbing himself with eel-slime.
- Scamp
- Scamps are used as assistants to the chefs on Umbriel for hot work, because heat does not bother them.
- Sea-Drake
- Sea-Drakes are immense fish found in the sea around Black Marsh. They are described as being "like a crocodile, but with paddles instead of legs".
- Sessile Crab
- Sessile crabs live on the floor of the sump of Umbriel. They are described as having squat, thorny bodies, with venomous claws on the end of twenty-foot-long yellow and viridian tentacles.
- Sheartooth
- Shearteeth are a type of fish found in the Sump on Umbriel. They have a "maw full of teeth", they can reach at least fifteen feet long, have a long long whip-like tail, dual swimming fins on the underside, "teeth that would shame a shark", and a tough hide. They are usually non-aggressive but will attack someone if the sump considers them a threat. "Sheartooth loin" is harvested by Skraw for the kitchens of Umbriel; Annaïg received some (among other things) from a Skraw working for Glim, and Glim himself later ate a sheartooth steak.
- Shine
- Shines are wispy yellow airborne creatures, a harmless cousin of the will-o'-wisp. They are seen in the Old Imperial Quarter of Lilmoth.
- Silk Leech
- Used as an ingredient in the kitchens of Tamriel.
- Singe Anemone
- A type of anemone found in the Sump on Umbriel. They have stingers, and because Mere-Glim's scales protected him from them, he took over the job of collecting them.
- Slarjei
- A creature from Elsweyr, said to be better in the desert than horses.
- Soul-spinner
- Soul-spinners are creatures of Umbriel, responsible for harvesting souls. They catch souls in their lines, and then the larva fly down to the prey. The larvae are moth-like and roughly as big as a person, with a round black head that only contains a needle. They are six-legged, and each leg ends in a similar needle. When they fly down to Nirn, they become ethereal and leave a silvery thread behind.
- Snapadder
- Snapadders are a type of snake. Annaïg uses the venom, which is bright green in color, in a dish as part of the cooking competition for the lords of Umbriel.
- Trogfish
- Trogfish are a type of fish found in Black Marsh. Mere-Glim would dive for them when he and Annaïg went to the levee at Yor-Tiq.
- Were-bear
- Hircine's drivers are were-bears: one in its human form looks like a massive albino Nord with blue tattoos and in beast form looks like "something between a man and a bear".
- Whip-poor-will
- Attrebus hears whip-poor-wills in County Bravil. Referred to as just "wills".
- Wisperill
- Wisperills are luminescent films which float through the air in the realm of the Hist. They perform slow, colorful, aerial dances in the air. They were named by Mere-Glim and Fhena when Umbriel is brought to the realm.
- Zilh Worm
- A type of worm found on Umbriel, known to be a parasite. Toel thinks of this when Annaïg tries to explain the concept of pregnancy.