Orvid will be found at Rinon's after Cassius' departure looking for "Grade-A product". What is that product? A special mushroom he asks you to find in Mushroom Hunt after you complete the Perzel Farm Monsters quest.
Prologue (After Departure): At Rinon General Goods in the City of Rolent.
Prologue (After Perzel Farm): Near the booth at the Rolent Landing Pad in the City of Rolent.
Prologue (After Liberl Media): ???