Well, it's here: the Thirteenth Night before Yule.

So potent a power is Yule that the Thirteen Nights cast a sort of shadow before them, a kind of inverse Yule.

These are the year's darkest nights. In the darkness, monsters assemble, more and more each night. It is the season of the troll.

Troll Night they call it, the thirteenth before Mother Night. At the doorstep, they lay out offerings, but the doors themselves they ward and hammer-sign from within. Here and no further, the wardings and offerings say.

Word is, the trolls will be particularly bad this year. Bad governance, or the threat thereof, always angers the beings of the land. 

Thirteen nights from now, we'll gather together to bring up the Light out of Darkness.

But for now, the Darkness gathers.

Let the wise be on their guard.