Penthesilea represents the instinct of the feminine "underdog." It is the passion that comes to a woman who "fights to the end," and finds that even if she loses an endeavor, she draws life and vitality from the attempt at fighting for what's right.
Penthesilea was an Amazonian queen in Greek mythology, the daughter of Ares and Otrera and the sister of Hippolyta. Penthesilea accidentally killed Hippolyta with a spear when they were hunting deer. Penthesilea was suddenly in so much grief that she wished only to die, but, as a warrior and an Amazon, she was only allowed to do so in battle. She, therefore, set out to join in the Trojan War, fighting on the side of Troy.
She came to Troy to prove to others that her people, the Amazons, are great warriors and can share the hardships of war and to appease the gods for accidentally killing her sister Hippolyta while hunting. She arrived with twelve companions and promised the Trojans that she would kill Achilles. Penthesilea was such an effective warrior because, unlike most Amazons who were missing a single breast, Penthesilea had both breasts cut off. On her first and only day of fighting, Penthesilea kills many men and fights with Ajax, although there is no clear victor before she comes to fight Achilles, Penthesilea had tried to fight Ajax but he laughed off her attempts, thinking her an unfit adversary. With only one blow Achilles pierces her breastplate then proceeds to impale both her and her horse. At first he mocks her corpse until he removes her helmet and feels intensely regretful.
Sometimes one must fight, simply because being laughed at is a kind of death in itself - the death of one's dignity, the sanctity of one's purpose in life, preserved, can be a victory in itself, more important than achieving a specific goal. Many people who have left jobs that were wrong for them, or relationships that were wrong for them, know this.