One day, mysterious portals appeared in every corner of the world, and many strange monsters that should not exist in reality came out of those portals, killing every living thing in their way. Some people were awakened to become slayers, and they fought to drive those monsters away successfully. But that was not the end, but the beginning of everything. You will play as an MC in a world three years after the invasion. What will happen to your story and your fate? Only you can decide.