Sara Trantoul was Leon Belmont's betrothed, his beloved companion who he would one day marry. As the daughter of a wealthy landowner, she was adored by all. When monsters began appearing in his domain, Leon struggled against the Catholic Church's restriction that he not fight any unauthorized battles. While such events were underway, the time was right for Walter Bernhard to swoop in and kidnap her, to use her abduction to goad Leon into a battle at his castle. When Mathias told him where he had to go, Leon raced to the castle, destroyed the five guardians that blocked the way, and found Sara in Walter's possession; having vampirized her, extracting his pleasure, she was of no longer need to Walter.

Leon took her to Rinaldo's cottage where her vampirism was diagnosed. The only way to cure her condition, Rindaldo informed, lay in the timely defeat of Walter. But this was an impossible task under these conditions. Knowing that her doom was imminent, Sara volunteered to offer her spirit to the cause--she would allow Leon to strike her down, which would combine her soul with his hatred to transform the Whip of Alchemy into the all-powerful Vampire Killer and counter the ebony stone's effects, this so that no other would ever suffer her cursed fate. Leon had no other choice, and, with a deep sadness in his heart, he ended her pain with a swing of the whip. With its new power, Leon used the whip to vanquish both Walter and even the divine Death. Though Sara had perished for the cause, her very essence inspired Leon to honor her dying wish.