|This article is about the polemarch. You may be looking for the athlete.|
- "*Cough, cough* Misthios rat! Did you think defeating me would bring you riches? Ah! You will not survive long enough to receive your bounty! My sworn brother General Heraclius is coming, and the fury of his forces will obliterate you and your Athenian masters! Prepare to *gasp*... face the wrath of Sparta!"
- ―Dying Erastos to the mercenaries hired by Athenian, 431 BCE[src]-[m]
In 431 BCE, during the war, the Athenians got the information about that Spartan polemarch Eustace will soon join the field in Arkadia, and attack Athens. Thus of this, the Athenians hired the misthios to take down Eustace. Little they didn't know, Eustace isn't alone. At night, the misthios infiltrate the Spartan camp in Arkadia first, and gather intelligence on Eustace's location by interrogate a Spartan hypaspist. The Spartan hypaspist sooner defeat by the misthios, and he reveal that Eustace is already in Arkadia resting in a nearby city before his death, and there are two more Spartan generals is preparing to attack Athens, Erastos is one of them.
After the death of Eustace, the Athenian scouts have reported that general Erastos is in a Korinthian city and will soon lead his troops towards Athens. In a temple, the misthios killed Erastos, and he warn the misthios that his sworn brother general Heraclius will obliterate them and Athenian.