Beyond the Boundary is a 2013 supernatural Japanese anime series based on the light novels written by Nagomu Torii and illustrated by Chise Kamoi. One day high-school student Akihito Kanbara instinctively goes to save his fellow schoolmate, Mirai Kuriyama who he thinks is committing suicide. However Mirai stabs Akihito with a sword made of her own blood and discovers that Akihito is an immortal "half-youmu"—the offspring of a supernatural creature called a youmu and a human. After learning that Mirai is a Spirit World Warrior and lacks the confidence to slay youmu, the two form an unlikely pair when Akihito decides to help her regain her confidence to kill youmu so that she may stop attempting to kill him as practice.