|Franchise||The Lord of the Rings|
|Vehicles and/or Gadgets||None|
|Occupation||Mordor Mountain Trolls|
The Olog-hai are not mentioned by name in The Lord of the Rings; the term appears only in the Appendices. They were bred by Sauron in the late Third Age possibly for the same reason Saruman bred the Uruk-hai, for improvement and less vulnerability to sunlight. They lived primarily in Mordor and in southern Mirkwood. However, they are described as being in the Battle of the Morannon at the Black Gate, where Pippin saves his friend Beregond from one. It is possible that some Olog-hai were also present at the Battle of the Pelennor Fields. The Olog-hai are described as being taller than a man, and covered in spiky scales, carrying war hammers, large swords or spiked maces, and bucklers, and having claws and, on occasion, tusks. It is mentioned that After the War of the Ring, all of the Olog-hai were extinct.
- One of them made an additional appearance in Riddle-earth.