Caestus is immortal and can create energy. Creating energy damages his body, but being immortal he can't die from this damage. So when the Forduria are running out of energy sources, it spells eternal damnation for Caestus. The Forduria capture Caestus and force him to power their nation. Just like sticking your arm in a hot oven, Caestus must endure this pain for the Forduria to continue existing.

Even with Caestus' many powers he is considerably weak. The Forduria use blue armor called a Shield Caster which covers the user's body completely. This armor is the strongest in existence and must be fitted to the individual, something Caestus will never have access to.

Not all Shield Casters are equally strong and strength varies greatly depending on the individual. The strength of the armor depends on the current Courage of the individual. The braver the soldier, the stronger their armor. Once the user begins to have doubts, or fears their enemy, their armor weakens and their blue fades. Making your enemy fear you will be their quickest defeat.

Mercy, a shield caster user finds Caestus and breaks him out of Forduria. She is from Karatha, an oppressed nation and race. Half of Karatha is now filled with monsters the Forduria call Atharak. Mercy believes the Forduria were doing experiments on Karths (short for Karathans) to explain the monsters and wants their oppressive actions to end. So she steals Caestus from them, their unlimited power source and only chance at discovering true immortality.

Caestus and Mercy must now escape the Forduria, travel through the devastated half of Karatha, and reach the still intact half of Karatha to finally be outside of Forduria's reach. But Caestus has limits and can only take so much pain and suffering. Once his will is fully broken...
his story will end.