Take my word for it, these bastards don't go down easy.
And don't be fooled by the name neither. Sure, they can look like 10' tall fiends, pale as a fresh snowstorm. Goat legs, tail, horns, the works. Breath that'll kill you on the spot, like being blasted with all the fury of an antarctic blizzard in winter. But that ain't the worst of it. You can fight a monster if you know it's there. Learn its weaknesses, be all strategic. But if you ain't even seen it… well, be prepared to watch the bodies start pilin' up.
The Snow Devil is in truth a monstrous spirit which can manifest in three different ways, although if any form is slain, the spirit is banished to the elemental planes. Each form is not to be trifled with and deadly in its own right. Each has a set of strengths. Each has a set of weaknesses. Learn them all if you expect to survive an encounter with one.
Changing from one form to another can take as long as a half hour, though this shortens with age. A Snow Devil can live for thousands of years.
The most physically intimidating and formidable form is the one after which it is most obviously named. At least ten feet tall, with the typical features of a devil, skin the color and temperature of freshly fallen snow, and eyes like chunks of amber. Horns like gnarled icicles spring from its forehead.
In Fiend form, a Snow Devil has two main methods of attack: a touch that drains warmth, most likely causing instant frostbite, and a blast of icy breath that chills and shreds flesh with the force of a thousand tiny icicles blown out at great speed.
As a Fiend, Snow Devils have great strength and their hides are quite tough. Younger Devils tend to assume this form more frequently as they revel in the physical power.
Being an elemental creature Fiends are, as expected, especially vulnerable to heat and fire.
In Ice Ghoul form, Snow Devils are less physically intimidating but more horrifying. They look quite bestial and appear to be humans that have been twisted into a grotesque combination of animal, human, and elemental. Their skin is the sickly shade and consistency of wax. Their teeth and claws are sharp, pointed, clear, and have the same chilling effect as a Fiend's touch. They range in height and build, but are never outside the norm for humans.
An Ice Ghoul does not have the same vulnerabilities to heat and fire as a Fiend does, although they will become physically weak in above-freezing temperatures. Their flesh is naturally tough, though not nearly as much as that of a Fiend.
A common Ice Ghoul tactic is to hide outdoors and pick off the weak and unwary during the dark winter months.
Cadaverous Old Man
The weakest, yet in some ways most dangerous, form is that of the Cadaverous Old Man. In this form the Snow Devil is tall (over 6') and quite slender. They look human, although perhaps a bit sickly, with gaunt cheeks and sunken eyes. Their voices are invariably deep yet weak as they must talk through near-constant coughing and wheezing. They have the typical skin, hair, and eye color of an albino.
Physically, the Cadaverous Old Man is neither imposing nor difficult to best. They have the strength and constitution one would expect from such an old and frail-looking man. Don't completely underestimate them too much, though, as they can be quite stealthy.
They have two abilities which make them both subtle and dangerous opponents: weather control and the dimming touch.
The presence of a Cadaverous Old Man causes winters to become both longer and fiercer. Folks will talk about how spring is taking longer than normal to appear or that they've never seen so many storms in a single season. During this time, of course, an old man will have appeared on the road, seeking solace and assistance while he lives out his "last few years."
Being physically unimposing, a Cadaverous Old Man does his best to avoid combat. If necessary, he will use his dimming touch on an attacker in an attempt to escape and hide. This attack causes the victim's vision to permanently cloud over, as though seeing through an endless blizzard. Their pupils disappear and the rest of the eye turns an icy blue color. A victim of this attack experiences life as though in constant partial light, receiving any relevant penalties.
A clever Snow Devil tends to enter town as the Cadaverous Old Man and take up residence. While there, the temperature drops and storms come in. When hungry, he will slip away from view, turn into the Ice Ghoul, pick off the easiest targets, and return before anyone has noticed his absence. Typically the townsfolk will assume an animal of some kind is hanging around and attempt to hunt it down. If cornered, the Cadaverous Old Man will use his dimming sight attack to confuse his attackers and escape. He may come back later in Fiend form in order to exact retribution. There have been more than a few instances where a Snow Devil has so weakened a village that the creature is able to kill every living soul in Fiend form.
Younger Snow Devils (no more than a few hundred years old) tend to stay mostly in Fiend form and attack any group or individual they feel confident they can take. While rare, there have been sightings of them wandering the snowy wastes in packs.