When you talk to Brenna outside the castle and have an extra space in your party, tell her it is too dangerous. She will give you a free Battle Axe and Idem Scale.
In the town outside Gwernia castle, there is a house with a lean-to built on. Inside is a bag with an Inferno Flask, a powerful item for Godric, or anyone with Alchemy.
Return to Oriana's after starting for the Mirari city. She will relate a tale and give you the spell of Strength for free (if you did not already get it from her).
After going over the bridge out of town, turn left onto the beach and turn right at the shrubbery to find a path leading upwards. You will find a campsite, and a short intermission for your journal. Inside a trapped chest is the Chaos Sword. This is a powerful sword that poisons, but requires a 25 Strength to wield.