Wikipedia
The troll-men of Far Harad are a fictional race (or a subset of a race) from J. R. R. Tolkien's epic fantasy book, The Lord of the Rings.
In the third volume, The Return of the King, Tolkien makes a passing reference to "black men like half-trolls" fighting in the Battle of the Pelennor Fields:
"... Easterlings with axes, and Variags of Khand, Southrons in scarlet, and out of Far Harad black men like half-trolls with white eyes and red tongues."
He later mentions "troll-men" as being amongst those driven off by the knights of Dol Amroth.
"...East rode the knights of Dol Amroth driving the enemy before them: troll-men and Variags and orcs that hated the sunlight."
It is commonly assumed by readers that these two references apply to the same group, though there are of course exceptions. There is disagreement on whether they were just large Men who are being compared to Trolls, and thus another group of Southrons (Haradrim), or some sort of crossbreed between the two races. Supporters of the latter interpretation point to the similar terms "half-orcs" and "goblin-men", appearing in the same book (chiefly in the second volume, The Two Towers), and "Orc-men" and "Man-orcs", appearing in later writings (published in Morgoth's Ring) — all applied to the products of Sauron and Saruman's Orc-Man breeding programs. (The interpretation of these terms as referring to specific "breeds", especially with the Uruk-hai, who had Mannish blood, is another source of disagreement.)