Within many anime series, I have noticed that there are many recurring mythological themes and characters. A series may have a connection to the actual myth or creatures/persons may show up in a series. Here is a myth that is connected to an anime series.
Susanou and Yamata - no - Orochi
Druing the beginning of the world, the god, Izanagi, and the goddess, Izanami bore many children. Three of these children were Amaterasu, Tukuyomi, and Susanou. The last to be born was Kagutuchi, who was a spirit of fire. Izanami was burned during the birth and disappeared. Izanagi had uncontrollable despair and destroyed Kagutchi. Kagutchi was later reborn as the spirit of minerals.
Izanagi then ordered Amaterasu to govern the sun, Tukuyomi to govern the moon, and Susanou to govern the sea. Susanou, though, didn't take his charge seriously. He wanted to visit his mother in the Land of Yomi (similar to the Land of the Dead or Hades, from what I gather from the story). He went to see his sister Amaterasu, she did not trust him coming to her territory since he didn't take care of his own. But after gaining her trust he was allowed in.
Upon entering her territory, he became mischievous and conceited. One of his actions frightened Amaterasu to hide in a cave with a rock shutting her in. By doing this the world went black without her light. The gods and goddesses convened to think of a plan to bring her out. Finally they were able to entice her out of the cave with her own reflection and light came back to the world.
As punishment, Susanou had his hair cut, his nails pulled, have his treasures confiscated and he was exiled from the land of the gods.
One day while following the course of a river he comes across a couple and their daughter crying. He asks them what is the matter. They responded that they had eight daughters and that once a year an eight headed dragon with eight tails, Yamata-no-Orochi, came once a year demanding one of them. The dragon would devour the daughter and leave until the next year, now they were down to their last daughter, Kushinada, and the dragon would be coming the next day.