A Business Opportunity Quest Walkthrough
How to start: Free the prisoner in Artemisia Fort.
You’ll eventually find Markos chained up on the island of Kos, towards the middle of the island and not far from the Highlands of Asklepiades. There will be a small prison underneath some shelter. Unlock the cage and carry Markos to his vineyard up the hill. He will then tell you about his “mama”, before asking you to take some wine to the Cerberus. He never exactly eludes as to whether he means the three headed dog or something else.
Head to the waypoint to find a house near the Kos Herb Fields. The soldier in the courtyard is the one you are looking for. He’ll be sceptical of the “peace offering” and offer you to drink with him. If you do so, he will claim the wine is poisoned, so return to Markos to find out that it isn’t really the case, just really bad. It turns out though that the soldier has two brothers, hence the Cerberus moniker.