Niflheim Yowlers
by HåvardThe large furry hound-like creatures known as Niflheim Yowlers are said to be the spawn of Garm the Demon Hound of Niflheim. While they roam freely on that Outer Plane, they can also be found in the Northern Reaches of Mystara, sometimes even as guard animals for powerful Human Jarls or Frost Giants.
In terms of monster stats, they are similar to regular Yowlers (AC9) or Yeth Hounds in other editions except that they cannot fly. They are immune to cold damage.