Giant-kin - Trolls

Trolls are a bane for many races, especially in Europe. They are loosely connected to other giants, and are primitive creatures originally hailing from Jotunnheimr. They speak giant, have strong malodourous smells drifting off them, have long sharp claws & teeth, gnarly skin, long rank hair, green or blue skin, sharp teeth, and the horrific ability to regenerate damage. Only fire or acid seems to work in preventing the regeneration.
Originally living in Jotunnheimr, the majority of trolls escaped to Midgard due to the effects of the regions of extreme cold, to the hill giants constantly trying to eat them. They still exist there and have many different varieties, some of which exist on Midgard. A few were brought to the Material Plane to be used as guards and hunters for the larger giants. Some legends speak of trolls mating with a few humans, though this is apocryphal to say the least, as no-one would actively admit to such an act unless under duress or clearly not of sound mind.
The trolls have spread out from the lands they originally arrived in and can be found to some extent in many European lands, and a few regions just on the edges of this. They haven't travelled further as they are now starting to encounter greater threats, especially from indigenous monsters, and human heroes in these lands.
It is seen by many heroes a great honour to be able to kill a troll, and return with a body part to show it is dead. Sometimes the hero, and the people they are trying to impress, get the shock of their lives when the part starts to move, and eventually starts to grow the remainder of the troll. Because of this, some evil beings look to harness this shock value for their own forces. Orcs, goblins, black elves, hobgoblins and the like all try to get one or two into their forces to act as shock troops.
Some societies have specialists who target trolls specifically and keep them in manageable numbers. The Dwarves and Norseman are regularly reported to have specialist warriors called Troll Slayers who know all the tricks & tactics of killing trolls, and know the mindset of the trolls they hunt. Most sensible races keep trolls far far away from their lands knowing how deadly they are.