Cold-blooded and ferocious demon Blood lives inside a cave and has been trapped in an impenetrable wall of ice for decades. His only goal is to find the Tear Jewel, the purest tear shed by a human at death's door. So far, all of his victims have failed to give Blood what he wants until he meets his newest prey: 18-year-old Ishuca Lake Sierra Vise Ell.

However, Ishuca is unlike any other human Blood has ever met. In the presence of the demon, Ishuca never cowers in fear and even wishes to be eaten by Blood, as he is soon to die due to a heart condition. Although taken aback by Ishuca's kindhearted nature, Blood warms up to the boy and his tragic circumstances.

Sadly, Ishuca's illness rapidly catches up to him and he is soon on his deathbed. Wanting to save him, Blood manages to shed the Tear Jewel, which he uses to revive Ishuca. Unaware of everything that happened, Ishuca asks Blood if he can join the demon on his next adventure. With Blood now also free from his prison, he agrees to allow his partially-human companion to accompany him into the unknown that awaits them.