Dire trolls are a small number of trolls that are strikingly larger and more heavily muscled than the rest of their brethren. There is no racial distinction between them and the rest of the troll race. A variety of reasons might be behind this unusual size and musculature. For example, dire trolls might have been altered alchemically or magically. They might also simply have been born larger than average (but it is not very probable). Regardless of the day-to-day prejudices that these trolls must contend with from other races, dire trolls are not regarded as monstrous by other trolls.
These trolls are much larger and more fearsome than their smaller brothers and sisters. They are very rare, and found deep in troll territories such as the Sunken Temple and Zul'Gurub. Dire trolls are either enchanted, cursed or mutated through alchemical processes to become the gorilla-like trolls they are.
They have many roles. usually their purpose is to kill. For the Atal'ai of the Sunken Temple, they are warriors, as well as Atal'alarion, who seems to be a huge, guardian troll of a statue. He is summoned, which suggests he is not natural. Among the Zandalar Tribe, Jin'rokh the Breaker appears to be a popular figure. The Gurubashi Berserkers of Zul'Gurub are also dire trolls. Grizzle has been imprisoned and he fights in the shows of dark iron dwarves.
In Wrath of the Lich King
The Scourge is producing dire trolls called "Blightbloods" by blighting Drakkari trolls with crystallized Blight. However, they never got to action because players stopped Drakuru's intentions.