The Mystic Falls Codex

The Mikaelsons' true firstborn, handed to Dahlia as payment and reported dead of plague. She was raised as Dahlia's weapon and held in the same cycle — a century's sleep for every year awake — for a thousand years, believing her mother had sold her — which was true — and that her family would not want her, which was not.

She turns up in New Orleans in the 21st century claiming to be their sister, is disbelieved for most of a season, and then becomes the person who actually solves things. Nearly every workable spell in The Originals is hers: killing Dahlia, containing the Hollow, keeping Hope alive. She marries Keelin, a werewolf doctor, and gets one of the very few uncomplicated happy endings in the franchise.