Legend of Duo

In the early 21st century, mankind's fate is sealed after losing "purana," an essence of living force that supports all life forms. A vampire named Duo, unwilling to watch humanity go extinct, reveals the secret of purana to humans, saving them from destruction. But just as Prometheus in Greek mythology was punished for bringing fire to mankind, Duo is punished for breaking the taboo. The vampire sent to punish him is Zieg, Duo's best friend, or, more than the best friend.