Derayd - Moon of Boundary Balance

Once the chaos took shape. The twin worlds were protected by the gods and goddesses. The things that drove the elements, the things that drove the energy and many things were divided. In this world called for twins constantly, and within it, there was time floating with the world of elements imbued with one another. The buoyancy and spirit guides, acted under the power of the gods most powerful to demonstrate the balance of power, the moon, the axis that supports it. Either way, these orders are completely unknown to welcome the world beyond. There is an old story about the two moons, the imbalance between the twins and the two warriors that will come with grace. The spirit of evil has come to break this, the name is the key to the imbalance of power.

Kenichi, a high-school student and member of a kendo club, walks back home when he sees that the moon has split in half! Just after which an earthquake leaves Tokyo in ruins. Kenchi is knocked unconscious, but hears a female voice saying he was the key to ending the demons in "Twin World". When he awakes, he finds himself in a parallel world of swords and witchcraft, where he meets the little fairy Bessy and a young swordsman called Ledan. After becoming friends they find they must work to save both worlds from demons and start a quest of two sacred objects that they need to save the world.

note: The manga has been reprinted in a normal tankoubon size with only Akiyama Tamayo noted as author.