In Curse Of Strahd, the Pack caught wind of this plan when ridding the winery's occupiers. Alongside Davian Martikov, they traveled to retrieve the Stone from the hill-folk, and came upon the scene at the end of the ritual. Ghalwin Forrester reached his hand into the effigy to remove the stone, but was too late to stop Wintersplinter's birth, and the blight began thrashing The Pack with powerful branches and grasping limbs.
Using a Plant Slayer that had been embedded in the nearby Gulthias Tree, Ghalwin eventually felled the Wintersplinter, and the adventurers killed the remaining members who had created it.