Legend of Duo

In 2000s, human beings have lost their purana, which are essential for living things.

It means that the human species is going to die.

However, a vampire saves the human beings from extinction by revealing the secret of purana to them.

In a mythical era, there was a god who was punished eternally because he had brought the fire to the human beings.

Like him, the vampire will be punished because he breaks the taboo to tell the secret of purana to human beings.

That vampire is named Duo, and the vampire who punish him is Zieg.

They used to be good friends...