The Olog-hai had none of the old Troll vulnerabilities: they were very intelligent and able to endure the Sun. For this reason they were seen by some to be giant Orcs (though surpassing even the Uruk-hai in size and power), but they were definitely of Troll stock.
Olog-hai are described as being taller than a man, and covered in horny scales, carrying hammers and bucklers in their claws, though there is no way of knowing whether this description applies to all of the Olog-hai, or just to those in the battle.[source?]
 Portrayal in Adaptations
1982-97: Middle-earth Role Playing:
- Olog-hai, also called Black Trolls, were bred by Sauron from lesser Troll stock. They are nine to eleven feet in height, and have black, scaly hides. Individual Olog-hai include Rogrog, Umagaur and Lugronk.
- Olog-hai were shown as the shock troops in the Siege of Minas Tirith, sporting armor and the famed war hammers alluded to in the appendices. These Olog-hai were not shown talking in any speech other than grunts. They differ from the other Trolls depicted in Peter Jackson's The Lord of the Rings in that they have more forward-facing eyes as well as hair on their bodies, suggesting that they are a more advanced form of Troll. They are usually gray to black in color. They have twenty-four teeth. Their eyes are also bright orange, showing their evil connection with Sauron.
- ↑ 1.0 1.1 1.2 J.R.R. Tolkien, The Lord of the Rings, Appendix F, "The Languages and Peoples of the Third Age", "Of Other Races"
- ↑ J.R.R. Tolkien, "Words, Phrases and Passages in Various Tongues in The Lord of the Rings", in Parma Eldalamberon XVII (edited by Christopher Gilson), p. 136
- ↑ R. Mark Colburn, Peter C. Fenlon, John D. Ruemmler, Terry K. Amthor, Jessica M. Ney (1989), Lords of Middle-earth Vol III: Hobbits, Dwarves, Ents, Orcs & Trolls (#8004)
- ↑ S. Coleman Charlton (1993), Middle-earth Role Playing (2nd edition, hardcover) (#2000)
- ↑ Ruth Sochard Pitt, Jeff O'Hare, Peter C. Fenlon, Jr. (1994), Creatures of Middle-earth (2nd edition) (#2012)
- ↑ Graham Staplehurst, Heike Kubasch (1995), Angmar (2nd edition) (#2018)
- ↑ 7.0 7.1 Peter C. Fenlon, Jr. (1994), Moria (2nd edition) (#2011)