Ballad x Opera

An Angel and a Demon have descended to earth with a mission but, by mistake, they ended up killing a human. Haruto, who has no reason to live, accepts his death but for some inexplicable circumstances, his soul cannot be brought to heaven and now he is a wandering soul. With a mission to accomplish and the guilt of having killed someone weighing heavily on him, the angel asks Haruto to become a Shinigami and help them out. In exchange, he will give Haruto something that will change his life' and his future forever. Will Haruto, who is like an empty shell, find a reason to live by being a Shinigami?