"The Impregnable <<Dreadnought>>"

1999. A collision with a meteorite created a hole in the Earth that connected it to another world. While the bewildered Earth side struggled with this, one of the two great powers in the other world, the Lemuria Federation, launched an invasion of Earth. The Earth side, struggling against the magic of the other world, sought help from the other nation in that world, the Astria Kingdom, and successfully developed a technology called sorcery. With the emergence of sorcery, the war reached a stalemate, and finally in 2002, a ceasefire was established between Earth and the Lemuria Federation. Fifty years later. The Lemuria Federation and Earth's nations continued to repeat ceasefires and warfare, somehow maintaining a balance. In the midst of this, a single Japanese boy descended upon the border region between Astria and Lemuria in the other world. His name was Yuki Mamoru. Also known as Sir Dreadnought. He was one of the forty-eight knights who supported the Astria Kingdom.