Distarter of Astral

[Warning 17+] 100 years ago, a huge explosion occurred due to a volcanic eruption that caused the entire world to be destroyed and reduced the human population by up to 50%. Simultaneously with the explosion of the mountain, creatures called Astral Being suddenly appeared and attacked the rest of humanity. Some survivors immediately find out the appearance of the creatures and also fight the creatures with the available equipment. However, because human abilities are limited, these creatures cannot be defeated. Humans are forced to survive in various ways without fighting these creatures. After a long struggle, an organization called the Wlynina Association was formed to fight the creatures. And since the killing of my parents by the creature, I continue to be involved with the creatures. They are cruel, kill, evolve into humans, kill, and continue to kill humans. Their only goal is to destroy all humans on this earth. I was invited to join Wlynina Military School by someone. I got involved with the townspeople and made up my mind to guard this world against those Astral Beings.