The Uruks of Saruman used an Elf-rune wrought in white metal on the front of their iron helms. Saruman's vast army of Uruk-hai fought against King Théoden of Rohan and his people at the Helm's Deep. "Half-orcs" were as tall as Men and are never described simply as orcs, as the Uruk-hai frequently are. There were other creatures in Saruman's armies, and under his command in the Shire, that appear to have been hybrids. There are suggestions that the Uruk-hai were the result of crossbreeding orcs and men. In the War of the Ring, the Uruk-hai made up a large part of Saruman's army, together with the Dunlendings, man-enemies of Rohan. Uruk-hai were later bred by Saruman the White late in the Third Age, by his dark arts in the pits of Isengard. The Red Eye was also painted on their shields. The Uruks in the service of Barad-dûr used the symbol of the red Eye of Sauron. The Uruks first appeared about the year TA 2475, in which they came and conquered Ithilien in Gondor, and destroyed the city of Osgiliath. We came out of Isengard, and led you here, and we shall lead you back by the way we choose.THE LORD OF THE RINGS: THE TWO TOWERS,CHAPTER 3, "THE URUK-HAI". We are the servants of Saruman the Wise, The White Hand: The Hand that gives us man's-flesh to eat. We are the fighting Uruk-hai! We slew the great warrior.
In The Lord of the Rings, the term Uruk-hai refers chiefly to those who were bred in Isengard, and in one context are alternatively called Isengarders -while Uruks from Mordor are called either the Black Uruks or Uruks of Mordor. Uruk-hai (for short, Uruks) were the strongest species of Orc in Middle-earth, who at separate instances in the Third Age originated from Mordorand from Isengard.