Tri-Horn Wyverns are a mountainous species, living in high altitude areas among rocks and snow. The rough and rugged climate has bred a tough and hardened species, prepared to do battle with both the elements and other creatures. Their most distinctive feature is the three-horned crest mounted upon their head, for which they were named; these toughened spikes are powerful weapons, used to battle against predators, prey and fellow Tri-Horn Wyverns. Both males and females of this species fight for territory and resources, and wear scars with pride. However, Tri-Horn wyverns have a soft side beneath their many spikes. They work in loyal packs, of which they are deeply protective; if one can gain their trust, Tri-Horn wyverns can be powerful allies through the mountains.

Dragons are highly-intelligent reptilian creatures that—from a human perspective, at least—appear to live forever. Many different varieties of dragon exist, each with their own unique qualities, habitats, and behavior. Adolescence in dragons is usually marked by the growth of a hatchling’s wings, although not all breeds of dragons grow wings and some breeds have other traits that indicate the beginning of maturation. In Galsreim, dragons and humans coexist peacefully.

Schlankermann, or Slenderman--called Slendy by Autumn--is a very mysterious Trihorn. He is silent, always very polite, and is extremely well-groomed at all times. He is very slender and quite tall, and does not have any facial features. None of the dragons from either the Republicator or Separator Territories know just where he came from or who he is. In fact, most of them have no idea he exists.

Slendy has the strange habit of following other dragons around for no apparent reason, his interests unknown to all but himself. He seems particularly interested in the hatchlings and young-adult dragons, as well as the Separator leaderess, Autumn the Generaless.

Throughout the years, Slendy's tale has gone from history to myth, from myth to legend, and from legend to creepypasta. It was only a recent occurrence that another dragon--Surge Snipe--believed he came up with the idea of Slendy, though he did not realize that stating so would lead to his inevitable doom.