Okay, there seems to be a cliche of mercs being money hoarding foreigners that loot and are loose with their morals, w/e.
So what are some historic exams that people can point me towards?
Herodotus has quite a bit about the Greek mercenaries who served Pharaoh Ahmose II in Egypt (c. 525 BC). They weren't rapacious looters as much as they were military settlers, trading their skill at close-order fighting for Egyptian gold. Not to be outdone, the Persian army of King Cambyses brought a contingent of mercenaries from the island of Samos with him when he came to conquer Egypt.
In the 5th century, you have the trials and tribulations of Xenophon and the 10,000: Greek mercenaries hired by a Persian prince to oust his brother, King Artaxerxes II Mnemon. The 10,000 -- comprised of a corp of Spartans under Clearchus and Greeks from various city-states -- won the Battle of Cunaxa but lost the war and were forced to retreat through hostile territory. The
Anabasis is the story of their march to the sea.
In the 3rd century BC, Darius III, the Persian king who opposed Alexander the Great, was said to have had 50,000 Greek mercenaries in his employ, including Memnon of Rhodes (he who provided me with this spiffy screen name) -- though Memnon wasn't strictly a mercenary, since he was related to the royal house by marriage (his wife, Barsine, was the daughter of Artabazus, a Persian satrap who was the grandson of one of Darius III royal predecessors, Artaxerxes II Mnemon, and cousin of Artaxerxes III Ochus). BUT, because of Alexander's ill treatment of the Greek mercs he captured after the Battle of Granicus River -- slaughtering most and condemning the rest to slavery -- most of the mercenaries remained loyal to Darius till the bitter end. It took the aforementioned Artabazus, who knew Alexander as a child and who was a guest-friend of Alexander's father King Philip II, to broker their surrender.
As for fiction: Steven Pressfield's
Tides of War presents what life may have been like for Greek mercenaries during the Peloponnesian War.
Hope this helps!
Scott