During a desperate surgery to save his life, Marc is fused with a parasitic monster. He eventually transforms into a Manna chimera —a beast with a human soul—and is forced to leave the Lighthouse.

Lower-class citizens who are treated as expendable laborers with no rights.

The surface of the Earth is now dominated by the , a terrifying biological system of monsters (Mana beasts) that consume the life force, or "ghalla," of living beings. To gather resources from the surface, elite soldiers known as Hunters must descend into this nightmare. The Story of Marc

In the far future, Earth has been ravaged by a geological catastrophe that wiped out most of humanity. The survivors now live aboard a massive floating fortress called the , a former aerial prison originally named Tartarus. A Dystopian Society

He is backstabbed by Charles , the power-hungry son of the current Lighthouse Master.

The story follows , the brave commander of the Hunters and heir-apparent to lead the Lighthouse. Marc’s world begins to crumble when he falls in love with Ran Bing , his second-in-command—a direct violation of the Lighthouse’s laws. His journey takes a tragic turn when:

To ensure survival, the Lighthouse operates under a brutal and cold caste system:

Emotions, particularly love, are strictly forbidden because they are believed to cause "instability" and attract the monsters below. The Threat Below