He had made the acquaintance of Phoibe and the Spartan misthios Kassandra at some point before the Peloponnesian War. Markos took Kassandra in under his wing, and got her into trouble in his schemes to get rich quick, including with the the Cyclops, a local thug. Eventually this situation was resolved, letting him get back to his scheming.
In 448 BCE, Markos found an unconscious Kassandra on the beaches of Kephallonia. Thinking that he could use her to perform various errands for him, Markos took her in and raised her to become a renowned mercenary on the island.
Sometime after Kassandra's departure from Kephallonia, Markos himself left the island as well, travelling to the island of Kos, setting up a wine business again. There, he got into trouble again, this time dealing with triplets known as the Cerberus.
Personality and characteristics
Markos' catchphrase was "Everybody benefits", usually preceded by a suggestion of how he and whoever he was talking with could help each other.