Deep within the forest, there live two witches: the beautiful marsh witch and the ugly forest witch. The two are engaged in a deadly war for supremacy. One day, the beautiful marsh witch encounters the legendary "one hundred cavalry", whom she then used magic summoned into the battle, in hope of gaining the upper hand against her rival.
Metallica is a beautiful marsh witch and also is the main character of the story. She hopes to get rid of her long time rival, the forest witch, and fill the world with marshland.
One hundred cavalry
One of the one hundred cavalry that Metallica summoned. Although looks small on the outside, it's able to wield a large broadsword. It has great power but has lost most of its ability to cast magic. It's also lost the notion of morality and will do brutal things in battle. It does not fully accept Metallica as its master. This character will act as the player's avatar.
Source: Wikipedia, "Majo to Hyakkihei", available under the CC-BY-SA License.