The word “Udûn” plays a large role in episode 6 of The Lord of the Rings: The Rings of Power. For one thing, it’s the title of the episode. For another, it’s the victory chant taken up by the orcs as Adar’s (Joseph Mawle) plan for the Southlands finally falls into place.
As episode 6 reveals, Adar didn’t simply want the hilt of Sauron’s old sword to wield it for himself. He wanted to use it to trigger the eruption of Orodruin (aka Mount Doom), thus destroying the Southlands and making them a place where the orcs can live without fear of sunlight. His plan succeeds despite the intervention of Galadriel (Morfydd Clark) and the Númenóreans, and the episode culminates with a game-changing volcanic explosion.
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When the orcs realize what is about to happen, they gleefully chant the word “Udûn.” In the Elvish Sindarin, Udûn means “dark pit” or “hell” — all the kinds of places where orcs would thrive. However, it also has a deeper meaning linked to the history of Middle-earth.
Udûn is another name for Utumno, the first fortress of the Dark Lord Morgoth (then called Melkor). Utumno has a similar meaning to Udûn: in the Elvish Quenya, it means “underworld.” Given the underworld connotations and Morgoth’s involvement, it’s clear Utumno was a pretty nasty place. However, it was destroyed when Morgoth was defeated in the First Age. Based on the orcs’ excited chants of “Udûn! Udûn!” it’s clear that Adar’s project was to create an Utumno 2.0.
In terms of geography, Udûn isn’t just the name of Morgoth’s fortress. It’s also the name of a valley in the northwest of Mordor, which is where the Black Gate is located in The Lord of the Rings. In her book The Atlas of Middle-earth, Karen Wynn Fonstad describes the symmetry of the vale of Udûn as being similar to a caldera, suggesting it could be a remnant of volcanic activity. However, she also notes that for that to be the case, the volcano would have had a base spanning 45 miles. For comparison, Mount Doom is seven miles across!
The episode title of “Udûn” likely derives from the Utumno comparison, but throughout this season we’ve been seeing how the orcs shaped the Southlands into Mordor. That means the name is also a nod to the future of the land we see get destroyed by the eruption.
Like with its discussion of mithril, the references to Udûn are another example of The Rings of Power gesturing to both the past and future of Middle-earth. This is just the latest in the show’s trend of taking small details from Tolkien’s work and incorporating them into the world’s larger mythology.