Stormstones are stone carvings that when illuminated with Electro provide a trail through the fog to guide you. There are several Stormstones in Autake Plains, which you can readily locate using the map below. These Stormstones are easy to find on a map.
After completing the quest players are awarded Light Up the Fog achievement and a chest. The achievement awards five Primogems, and the Chest awards 40 Primogems, 30000 Mora, and three Hero’s Wits.