[Cover is a Picrew by Crowesn]
The woman is a Gerudo woman from ancient times. She's lived as long as Ganondorf has due to her curse. She found a mask that was once used by a deranged madman. The mask grew into her mind and made her do things she regrets to this day.
Majora's Mask.
When a Knight from Hyrule gave her a blade, she used to kill innocents. The mask had finally gotten to her. She was able to remove it but still holds it dear to her along with the blade. The blade is a small dagger from the Gerudo town, a Scimitar. The Knight was one of her greatest friends, along with the Princess. When the two of them grew closer without her, she became jealous and ran away, and that's when she found the mask.
The source of her curse comes from the moon, where the mask gained its powers. She made a deal with it so that her soul wouldn't be damned by all the innocent people she had murdered.
She meets The Demon King while trying to get back into Hyrule, and that is where our story begins...