The Uruk-hai are fictional characters in J. R. R. Tolkien's fictional universe of Middle-earth. They are introduced in The Lord of the Rings as an advanced breed or breeds of Orcs that serve Sauron and Saruman. The first uruks appeared out of Mordor in attacks on Gondor in .
The name "Uruk-hai" has the element Uruk, which is a Black Speech word related to Orc, related to the word "Urko" in Tolkien's invented language of Quenya. The element hai means "folk", so "Uruk-hai" is "Orc-folk". A similar term is "Olog-hai" ("troll-folk"), used for a breed of especially strong and vicious trolls capable of surviving sunlight.
The Uruk-hai, described as very large black orcs of great strength, first appeared from Mordor about the year 2475 of the Third Age, when they briefly took Ithilien and the city of Osgiliath. These original Uruks were of Sauron's breeding, but Saruman bred his own, making further changes, such as resistance to sunlight and more upright stature. All Uruks were larger and stronger than other breeds of orc and consequently looked down upon and often bullied them.
In The Two Towers, Aragorn observes that the fallen Uruk-hai at Amon Hen were not like any breed of orc he has seen before. Treebeard speculates that Saruman had crossbred Orcs and Men. These orcs, who named themselves "the fighting Uruk-hai", made up a large part of Saruman's army, together with the Dunlendings and other human enemies of Rohan. They were faster, stronger, and larger than normal orcs, and could travel during the day without being weakened, although they still did not like it. Saruman's Uruk-hai fought against the Rohirrim at the Battles of the Fords of Isen, at the first of which King Théoden's son Théodred was killed, and at the Battle of the Hornburg, where the vast majority of the Uruks were defeated and destroyed.
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