Based on a manga by Mitsunaga Yasunori, serialized in Monthly Shounen Sirius. Hiyorimi Hiro relocates to a new city to reside with his older sister, but perishes before locating her. He subsequently awakens to a new existence as a servant to a Princess of the Monster Realm, who coincidentally employs his sister. Monsters soon emerge to attack or pester the princess because she is in line for the royal throne, and Hiro must protect her with his life (and repeated deaths). (Source: ANN)