Winterbole Forest

The vast expanse of the Winterbole Forest—known as the Shadowsong Forest by Woodsinger elves—defines the northern border of the Nentir Vale and the limit of Nerath's expansion at its height. It limits to the north with the mysterious Dayforge Mountains. The ancient trees of this forest have borne witness to the passing of epochs, and hidden beneath their dark canopies are the remains of empires long departed. Few souls brave enough to explore the primeval forest ever return, for countless horrors haunt the crumbled ruins. Within their woods lie ancient Arkhosian ruins and secret Shadowfell crossings. Home to a multitude of monsters and villains. The white dragon Bitterstrike holds sway over a large part of the forest. Several of the Winterbole's denizens, most notably the Tigerclaw barbarians and the Frost Witches, pay fealty to the dragon. The satyrs and the coniferous treants of the Winterbole contribute some of their ranks to the cadre of Bitterstrike's vassals, and they typically stand with the dragon when it becomes necessary to put down an incursion into the forest by humanoids.
The Tigerclaw barbarians consider themselves the real power to be reckoned with in the Winterbole. This wide-ranging band of humans and shifters were never brought under Nerath's sway, and remained uneasy neighbors of the empire at its height. They trade with the people of Nenlast at times, but in harsh winters they have also been known to attack the village and simply take the food and weapons they need. The Frost Witches are not nearly as numerous as the Tigerclaws, but their desire for domination is no less strong. Clenderi, the witches' leader, would like nothing better than to convince Bitterstrike  to join their cause in service to Cryonax.
A cult of blue-skinned humans known as the Frostbloods pay homage, with blood and sacrifice, to Cryonax as well. Only the wild folk know of their existence, and even among them the Frostbloods are shunned and condemned as cannibals and monsters. No one knows how many Frostblood cultists exist. Their organization is broken up into separate tribes that roam the frozen forest.
-The Pyramid of Shadows: In the depths of the Winterbole Forest, this bizarre extradimensional space full of weird monsters and strange magical effects holds creatures from all planes of existence since the Dawn War. The Pyramid of Shadows is one of many infernal prisons created to confine powerful beings. It exists beyond space and time, appearing in multiple places in the world and planes beyond.