Plane Prowler

The plane prowler, colloquially known as the Weather Wolf or Weather Beast, is a powerful and unpredictable predator known to attack both beasts and men. Thankfully it is only known to occur within the Kaiher valley, also known as the Rift.

A shadow sprung from nothing, he takes all he can get
But if you can learn to sense him, you might not die just yet
A warm wind in the winter? Frost on a summers day?
The weather beast is coming - you'd better run away

— Northern tribe proverb

The Plane Prowler has been aptly names by scholars since it's primary hunting method appears to be planeshifting in and surprising its prey. However, this, in combination with the very low rate of survival in en encounter with the beast, has also meant that the creature has remained highly elusive and very little is known about it's habitats.
Tradition dictates that it is possible to know in advance when a plane prowler is about to appear by monitoring the weather and local conditions for anomalies, such as a sudden fog or frost on an otherwise sunny day or a warm summers breeze or smell of fresh flowers during mid winter. These phenomena have given the prowler the nickname of weather beast or weather wolf.

Appearance

When a prowler does appear it is initially quite difficult to distinguish what it looks like, it appears blurred around the edges as if existing in two places at once. This is one of the reasons scholars suppose that the beast is planeshifting since similar effects can be observed during the use of planar shift spells, but not during local intraplane teleportation.
However, those few lucky enough to be alive after these first few moments of indistinctness has passed, describe the beast as vaguely wolf shaped although with higher shoulders and a more arching back. It appears to be covered in fur but examinations of pieces of it left behind indicates that the hairs are quite thick and almost crystalline in nature.

Habitat

The plane prowler is only known to appear in the Kaiher Valley in the far northwestregions of the Great Wastes. This valley is also known for being the location of many rifts between planes and that the interplane barriers appear significantly weakened there which may explain the appearance of the prowler. However which other planes the creature frequents is currently unknown.