Have you ever thought about war? Of course everyone has thought about it. However, this is not an ordinary war. This war, is not an ordinary war. This war is a war against the devil, if you are not careful once, the devil will easily possess you. This war occurred because of the opening of the gate between Gehenna, the demon world, and Assia, the human world. So, A military organization called Handonobu was formed. A military organization equipped with sacred weapons and deadly weapons. All weapons have been enchanted with spells and have also gone through several rituals. Demons will be more active at night, once the sun starts to set, demons will be very aggressive and their power level will increase by 35%.

Your uncle, Hiro, is a lieutenant colonel who serves as the vanguard in battle. He is a great katana master and also a martial artist. He was raised by his grandfather who is now a retired military man. Hiro is very kind to you, he has had the ambition to teach you swordsmanship since you were nine years old. He can carefully read the aura within you. One day, you stay at your grandmother's house to practice with your uncle, your mother also comes along to watch over you. cold night, of course. Since your grandmother's house is in the highlands, the night atmosphere is very cold. You are tired after practicing with your uncle all day, you sleep in the living room on a mattress with your uncle.Your uncle was fast asleep even though it was very cold. Meanwhile, your mother sleeps in your grandmother's room and your grandfather sleeps in his room