Stoneheart Peaks is a rugged mountain range characterized by steep cliffs and rocky outcrops, situated above the tree line. The climate is harsh and cold, often marked by snow near the peaks. The area features a network of ancient stone paths and large pictographs carved into the mountainside, some standing 20 to 30 feet tall, indicating historical significance. The peaks have been home to witches, and a notable witch's camp is located on the mountainside, featuring raised platforms and an overhang for shelter.
The Stoneheart Peaks are Sylvie's homeland, and she has not returned since she lost her power there. Among her people was the Eyrie — a select order who kept and rode great mountain birds: children were "marked for the Eyrie" at eleven or twelve, split from the community to live higher up under an old woman's mentorship, and trained as riders, bearing messages swiftly across the umbral region and reaching places otherwise cut off. (These birds are not to be confused with the Askavir, the singular titan-raptor of the range, which is an order of magnitude larger and the only one of its kind.) The peaks are also spoken of as a place where a Blessed Branch might be found, high in the crags.
A unique aspect of the peaks includes a compass anomaly that indicates a non-terrestrial reference. Stoneheart Peaks also leads to Verrow's Span, a village built into the cliffs, where local inhabitants have connections to the area’s history and lore.
More recently, the Stoneheart Peaks have revealed a cratered mountaintop that contains a small lake within a bowl-like depression. Steps have been cut into the stone, leading down to the lake's edge. The area shows signs of past habitation, with remnants of villages and houses that have crumbled over time, likely due to avalanches and other natural disasters. A colossal, grimacing face-like impression can be seen in the sky, reminiscent of behemoth-sized idols.
Adventurers encountered aggressive crabs while fishing at the lake. Sylvie and her companions used magic and archery to fend off the crabs, experiencing bulging distortions in the ground and sky with each casting of magic, as if an immense hand pressed into the sky. After harvesting the crabs for food, the group discovered a sheltered cleft used by Stone Weavers for camping. Sylvie experienced vivid dreams of disembodied voices and former associates, hinting at past events connected to the mountain. In the following days, Sylvie attempted to restore what had been lost from the mountaintop, culminating in a moment when a massive stone body tore through the sky above, descending toward the mountain.