Suppressing Weird People: I Guard the Century-Old Weird Asylum

After a hundred years of guarding, one person and one courtyard, why is he immortal and immune to all kinds of tricks? In an ambush on a rainy night, the taboo box fell into a remote shelter, and the peace was completely shattered. There are frequent riots, the secret organization is chasing after him, and the General Bureau of Secret Defense is hiding a conspiracy. What is hidden in his dusty past? When the taboo-level ghost awakens and the world falls into catastrophe, can this ghost-keeper who has been forgotten by the world suppress all the ghosts with one sword and guard the last piece of human fireworks?