Her own planet and everyone she loved were destroyed by the Horde before they joined Skeletor in Eternia. Skeletor was very nearly successful in Eternia’s takeover, but He-Man and all those who would fight by his side banished Skeletor and the Horde for good.
However, this feat came at a very great cost.
After the untimely death of He-Man, She-Ra came upon the realization that she too would not live forever. She was no longer going to waste her youth. He-Man bequeathed to her his prized possession; She-Ra was the only family he’d ever known. She-Ra took the Battle Axe, moved to a trendy part of town, joined an indie rock band as the lead singer, but still managed to kick ass and protect all of the alternative arts scenes. Protect them against what, you ask? Mostly poverty, unfulfillment, greed, and, some would say, the dark sides of their own selves.
She-Ra, however, never changed her name. All of her new-found friends just thought she was being clever or ironic; she just seemed so cool when she wielded that axe.
Dammit, she was cool when she wielded her axe. She was their hero.