Darker than Black

(SBurb never happened,) A few years ago, Rose did something because of a being in the back of her mind that sent her to a school for those society fears. There, the thing in the back of her mind grew to a size where she could no longer ignore it, no longer co-exist with it, no longer stand its near-constant noise... and so, desperate to have her mind as her own, she begins to kill.