Without Purpose Picture

According to the official mythology, the universe of Fabula Nova Crystallis is divided in half: the visible world, or the world of the living, and the invisible world, or the world of the dead. The two worlds must stay in balance, or the entire universe might be destroyed. Etro was created by the god Bhunivelze, who was a god who became the sole ruler of the world by defeating his mother, Mwynn, and banishing her into the world of the dead.

However, this did not satisfy him, as Bhunivelze believed all things were destined to die due to a curse laid on the world by his mother. In order to reach the realm of the dead and destroy her, Bhunivelze created the three deities: Pulse, Lindzei and Etro.

Etro was the second deity to be created after Pulse. The mythology at this point call Etro and the others fal'Cie, even if all other sources know them as the god and goddesses of Fabula Nova Crystallis lore. Bhunivelze immediately regretted having created Etro, because he had unknowingly created her as the exact image of Mwynn. Bhunivelze thus feared Etro and gave her no powers to create anything of her own. Bhunivelze then crystallized himself to sleep until his creations found the door to reach the realm of the dead.

While Pulse and Lindzei were busy creating the world and creating many more fal'Cie, Etro was lonely. She tore up her body and disappeared from the world, entering Valhalla, but from her blood humankind was born. Unlike the fal'Cie, who are immortal, the humans who were born out of Etro's sacrifice lived only to die.

Etro eventually found Mwynn in Valhalla as she was almost overtaken by the chaos of the world. Bhunivelze's goal of immortality caused an imbalance that would collapse the universe. Before disappearing into the chaos for good, Mwynn gave Etro the task of protecting the world balance. When people from the realm of the living died and they passed on to Valhalla through the Door of Souls, Etro greeted them and gave each a piece of the chaos to hold inside of them. This is what people would come to call "heart" and was their greatest strength without the people even realizing it.

~ Etro's Final Fantasy Wiki page. [link]

Although Etro never personally appears in the games, she's one of my favorite characters. I love her story, and how she messes everything up by trying to help.
Romulus and Remus
Without Purpose
The Mother, The Universe