Lord of the Rings Olog-Hai troll / Black troll

The Olog-hai, also known as Black Trolls, were a formidable breed of trolls that emerged during the final days of the War of the Ring, serving Sauron in Middle-earth. Standing between nine and eleven feet tall, they were distinguished by their black, scaly hides and fearsome demeanor. Although Tolkien suggests they appeared later in history, some accounts place them as early as the wars with Angmar. Notable Olog-hai include Rogrog of Angmar, Umagaur, and Lugronk.

Unlike traditional trolls, the Olog-hai lacked their typical vulnerabilities. They were highly intelligent, capable of strategy, and could endure sunlight without turning to stone—an ability attributed to Sauron's influence over them. His will not only bolstered their strength but also filled them with malice. Their cunning and ferocity led some to mistake them for giant Orcs, surpassing even the Uruk-hai in size and power. Others perceived them as monstrous, man-like figures. However, in both body and mind, they were undeniably trolls, yet far more advanced and terrifying than their lesser kin.