After waking up in a forest, the protagonist realizes he has become a ghost. However, he still retains his memories and knowledge from before his death. This marks the beginning of Shu Auroright's story. Using the power to drain life force and accumulate magic, he evolves and enhances his combat strength by analyzing magic. This is the tale of the protagonist, who becomes known as the Lord of the Underworld, and his partner, a witch, as they travel the world and encounter various adventures.