Trolls are the lovable blue-skinned brutes of the Hordes universe. Trollbloods traditionally live in loosely organized, tightly knit communities on the fringes of (or completely removed from) the rest of civilization in the Iron Kingdoms. The escalation of warfare in their lands has led to the trolls uniting as a people to defend their "kriels". They are the "protagonists" of the Hordes lore because they seek nothing other than to defend their home and people. That said, some of their characters (especially Hoarluk Doomshaper) are not very nice about it. Doomshaper himself is a mad racist who is totally in favour of wiping out all of humanity. Thankfully, most of the other characters hold him back to less extreme goals.
There are five kinds of Trollbloods: Pygmies, Trollkin, Trolls (Full-blood), Dire Trolls, and the gargantuan Troll Kings. All Troll models fall somewhere in this continuum and are tied together by their regenerative capabilities. Most Trollblood warriors and all Trollblood Warlocks are Trollkin, being the most human-like of Trollbloods, while Pygmies are their diminutive cousins. Full-blood Trolls and Dire Trolls comprise the warbeasts that Trollbloods have access to and are defined by their prodigious natural strength and astounding regenerative capabilities.