The Mystic Falls Codex

Tristan's sister, whom Klaus loved in the 11th century and Rebekah turned against his explicit wishes. She is arguably the first vampire genuinely driven mad by immortality, and she has had a thousand years to become very good at it.

She survives everything The Originals throws at her, is entombed in a wall by Klaus, is let out by Lucien, and turns up in the final season of Legacies as a season-long antagonist — the only thread connecting the 11th century directly to the last stretch of the franchise. Ken's spear kills her, shielding Hope, and she gets a Viking funeral.