【Book to be released on May 10th】 It is the year 1943, during World War II. In a desperate attempt to turn the tide of the war, the head of state of a European country on the brink of defeat performed a demonic summoning ritual, sacrificing not only enemies but also their own people. Despite the skepticism of those around him, the ritual succeeded. The summoned demon wielded supernatural powers and decimated the enemy forces. After fulfilling the contract, the demon was expected to return, but instead, it used the soldiers it had slain as sacrifices to summon more demons. These newly summoned demons, having no connection to the head of state who performed the initial ritual, killed everyone involved, including the head of state, thus freeing the demon from the contract. From that moment, the war between humans and demons began. --- About 100 years later, humanity was still fighting against the demons. Also posted on Kakuyomu.