They're actually a part of Norse mythology. In the Viking age, Berserkers were a group of warrior shamans with the totem animal of a bear, which is where the name Berserker was created.

Trolls are one of the most ubiquitous monsters that show up in fantasy tales. They’re in the Lord of the Rings, Dungeons and Dragons and Disney’s Frozen, to name but a few. But the origin of the ...