Will was born in the city of the dead, where he was raised by three undead. Although he was nurtured with love, Will questions his existence in this life-forbidding place where he is the only human alive. He discovers his three parents are secretly hiding something that may explain this mystery, and as if this weren't puzzling enough, he has yet to discover that still more secrets lie within him.

Five years have passed since Will learned Mary's secret, and he is now 13. His undead parents' lessons grow ever more difficult, but Will manages to stick to it. One day, Blood gives him an assignment requiring him to escape from the ruins in the city. Will desperately tries to fight his way out, but an odd sensation of malice stops him. It turns out that malice was coming from an unexpected source.

Will, who was to have an audience with the lord Ethelwald as a "Killing Wyvern," offers to gather private soldiers to eliminate the frequent damage caused by monsters. Ethel once shows an intimidating attitude to such an outlandish offer, but decides to identify Will and forgive it. Head to a bar where adventurers gather to find friends to fight with.