The dreugh are an ancient species of aquatic, octopus-like beastfolk, commonly hunted for their hide and the wax from their shells. They are sometimes known as water dreugh. For one year of their life, dreugh undergo karvinasim and emerge onto land as aggressive crustaceans to breed. During this period they are known as land dreugh or Billies. Unlike their aquatic counterparts, the land dreugh show no signs of their usual intelligence and kill indiscriminately, using powerful shock attacks and even going so far as to cocoon living victims in mud to feed their young.
Dreugh are found mostly in northern, western and eastern Tamriel, but can usually be found anywhere coastal. They are known to inhabit the Inner Sea and the Abecean Sea, migrating into the waterways of the Iliac Bay. Land dreugh can be found as far inland as Cyrodiil and Craglorn. Although altercations can happen when swimming in these waters, the dreugh are mild-mannered, and usually scavenge for food. Land dreugh bury their captured prey alive, in piles of hardened mud. After their year on land, dreugh undergo meff, where they digest their unneeded skin and organs and vomit the congealed remains as small fibrous balls called "grom". Dreugh are known to be immune to paralysis, poison and disease and resistant to magic, but have a low tolerance to frost. They can regenerate health in darkness and in water, but cannot enter holy places. Their infamous shock attacks are unique to land dreugh, and those in the water must rely on melee attacks. As well as using dreugh wax in alchemy, their hide is used by the Dunmer to make traditional armor and weapons.
The origins of the dreugh are clouded in myth. In the Iliac Bay region, they are rumored to be the remnants of a prehistoric civilization from long before the First Era. Some scholars argue that the land dreugh is actually a distant relative of the true dreugh from further back on the evolutionary timeline, perhaps even related to Spider Daedra. The ancient Chimer once had dealings with the dreugh; Tribunal Temple teachings speak of the treacherous "Altmer of the sea" and their castles of glass and coral. Their protracted conflict with Dunmer hunters is blamed for their devolved intelligence and the destruction of their civilization.
According to conflicting legends, the dreugh once ruled the world as tyrants, and Molag Bal had served as their chief. When the dead carapace of Bal's old image was dropped into the world from his interactions with Vivec, a Chimer child from Gnisis wore it to scare his village, but instead became the Ruddy Man. Vivec did battle with the Ruddy Man, and their fighting created the West Gash region of Vvardenfell. Vivec was victorious, and gave the carapace to the Queen of the Dreugh to guard; instead, the dreugh gave it to a wayward shaman of the House of Troubles, and the Ruddy Man appeared again ten years later at Tear. After defeating him a second time, Vivec gave the carapace to the devout and loyal mystics of the Number Room, who made it into "a philosopher's armor". According to the teachings of Mankar Camoran, the tyrannical dreugh-kings ruled over Mundus and enslaved the oceans before Lyg was destroyed by Mehrunes Dagon.
During the Interregnum, a dreugh known as the Ruddy Broodmother began terrorizing the roads around Molag Mar, killing pilgrim and Buoyant Armiger alike. The Ruddy Broodmother hid within the Dreudurai Glass Mine, and the Soulless One, with the help of a group of Ashlanders, drew it out of hiding and slew it. A pilgrim who survived the incident and fled into an ancestral tomb believed the creature to be the mythical Ruddy Man, though Ashlanders denied the its existence, claiming that the Broodmother was simply a powerful and cunning dreugh. The Buoyant Armigers considered the thought of the beast being the Ruddy Man borderline heresy. The captain of the Buoyant Armigers at the time suggested that if the Ruddy Broodmother truly was related to the creature of legend, that it might be a lesser creature "cut from the same cloth" as the Ruddy Man. 
- For game-specific information, see the Daggerfall, Morrowind, Oblivion, ESO, and Legends articles.
- Dreugh names
- Creating ESO: The Dreugh
- Brenus Astis' Journal — Brenus Astis
- Events of ESO
- 2920, Sun's Dawn — Carlovac Townway
- Njorlund Steel-Wind's dialogue in ESO
- Revolting Life Cycle of the Dreugh — Fronto Maecilius
- Events of Daggerfall
- Events of Morrowind
- Daggerfall User's Guide
- The 36 Lessons of Vivec — Vivec
- Mythic Dawn Commentaries — Mankar Camoran
- Captain Naros's dialogue during An Armiger's Duty