Penthesilea is the daughter of Ares and Otrera, the sister of Hippolyta, Antiope and Melanippe, and an Amazon queen. His participation in the Trojan War is described as follows: While hunting deer, he accidentally killed his brother Hippolyta with a spear. This unfortunate accident caused Penthesilea a lot of pain and all she wanted was to die. That's why he was easily persuaded to join the Trojan War. He defended the Trojans in this war.