The mighty Cerberus comes to Assassins Creed Odyssey in the form of a ship cosmetics named the Hounds Of Hades. Its found in a Legendary Chest in a secret location.
Hounds Of Hades
Cerberus was the mythical multi-headed dog that guarded the gates of the underworld, preventing the dead from leaving, and making sure that those who entered never left. From Greek Mythology.
To sail the seas on AC Odyssey with this legendary ship you must discover the location of the chest first. At the South East tip of Lakonia, there is a small island with a shipwreck next to it. A strip of land will be forming a line from the main island near this location.
The area you must visit is shown in the picture below.
Once you arrive summon Ikaros and scan the area. Your flying partner will spot the golden chest for you. Now dive into the water and navigate to the waypoint. Congratulations, you now command, Cerberus - the Hound Of Hades.
If you haven't yet, go collect The Minotaurs Revenge and add to your ship's cosmetic arsenal.