The Old Margreve Forest

In the eastern shadow of the Icespire mountains lies a vast forest known as the Old Margreve. For untold centuries its densely tangled leagues have been host to all kinds of beast and monster, but in the mid-6 th century it was somewhat tamed by Elves taking refuge after the carnage of the Demonwrath Wars that closely followed the terrors of the Ghoul Incursion.
For two centuries the The Qualinesti Elves thrived in the Heart of the Forest, until the Great Darkness came and they faced the choice of fading forever from the mortal world like their kin, the Silvanesti, or returning to their home in Qualimor to the east to help fight the demon hordes once more. Over the next four centuries Nature reclaimed the Margreve, its roots and vines choking and crumbling the Elven architecture and tunnels to ruin.
But residual Elven magic had left an overlap between the material plane and that of the Feywild, so that fey creatures both fair and foul began to populate the forest. By 1100 NE the forest was so alive with these beings that it was awakened, becoming a sort of living, sentient entity in its own right. Some say the witch Baba Yaga, whose presence in the world is first recorded around this time, is an expression of the forest’s fey sentience. Others say she is just the spirit of an old crone devoted to the evil sorcery of the Night Goddess, Hecate. Perhaps the truth lies somewhere in between?
Until recently the dark and forbidding forest was home to a nation of badger-riding Forest Gnomes, whose Hidden City in the trees, cloaked by illusion magic, was a hub of light, joy and hope. But something has poisoned the sentient mind of the enchanted forest of late, rotting it internally and turning it against itself, such that the Hidden City, known also as Treeholme, was utterly sacked by a host of vine golems. It is rumoured that Baba Yaga has managed to somehow restore some semblance of balance to the diseased forest, but it currently teeters on the brink of insanity. And if its fey inhabitants lose their minds to Chaos, the rest of the world should tremble at what comes next…