Aidyn Chronicles: The First Mage (Hints & tips)
Talk to Brenna outside the castle with an extra space in your party. Tell her it is too dangerous. She'll then give you a free Battle Axe and Idem Scale Armor.
In the town outside Gwernia Castle, there is a house with a lean-to on top. Go inside and you'll see a bag with an Inferno Flask. Give this to anyone with Alchemy.
Go over the bridge out of town and turn left onto the beach, then make a right at the shrubbery. Here you'll find a path. You will find a campsite, and a short intermission for your journal. Inside a chest here is the Chaos Sword. You'll need 25 strength to use it.
Go to the abandoned camp where you get the Chaos Sword and follow the trail north until you reach a path. Take that path to Erromon.