Impregnable Dreadnought

あらすじ

In 1999, a meteorite collision opened portals between Earth and a parallel world. The Lemuria Confederation from the parallel world invaded Earth, which responded by developing magic technology with the help of the Astoria Kingdom, another major power from the parallel world. This led to a stalemate and an armistice in 2002. For the next 50 years, Earth and the Lemuria Confederation engaged in cycles of war and truce, maintaining a fragile balance. The story centers on Yuuki Mamoru, a Japanese boy nicknamed Sir Dreadnought, who descends into the border zone between Astoria and Lemuria. He is one of the 48 knights supporting the Astoria Kingdom.