From the introduction:
We at Rookery Publications have been mulling for months how to present a bestiary that works for as many different roleplaying games as possible. What you hold in your (digital) hands is our first answer to that question: a wintry horror for use with any setting, with stats designed to be easily adapted to any RPG system. So, no matter your game of choice, you can use the chilly joys of Mother Hoarfrost.
This supplement was originally created as a festive gift for patrons of Inside the Rookery, our live-streamed, weekly panel show. There we are joined by guests from across the industry as we draw back the curtain on what happens behind the scenes of the games we all know and love. We also invite our viewers to ask questions and make comments as we go, ensuring everyone is involved.
Now Mother Hoarfrost is available for everyone to try.