the food source they represent isn't the sole properties of these berries. From their presence in Posada, they have been infused with the magic weave during the re-establishment of our link to the magical plane. They berries are used in the treatment of what is known as the fey's fever, called like this because of the glowing pink and yellowish marks appearing on the ill's torso area, propagating towards the limb and glowing stronger with time before disappearing completly after recovery. As few would know the name is properly given, as the disease is actually a pact being writtent between an Archfey and a future occultist. After weeks of fever and strange visions, if the sick person doesn't die from dehydratation and hunger, the contract will be signed and they will awake with occult powers granted by the ArchFey. The magical properties of the berries act as blockers between our plane and Feywild. Allowing the ill to be quickly restored to their normal self.