The advancement of the Sick Ones was inseparable from the diseases within their bodies. Every change in their afflictions was directly connected to the Old World Plague Focal World (Focus of Infection).
It could even be said that every advancement of a Sick One brought them one step closer to the Focus of Infection Center.
This was especially evident during the pathway stage. The Sick One had to find a door suited to their own affliction and use it to reach a Transfer Station closer to the Focus of Infection Center, where they underwent Silver Turbidity and composition.
The staff at the Transfer Station all served the will of the world directly.
At the same time, those Sick Ones who reached the Silver Circle were known as Old Day Diseased—the true Sick Ones recognized by the will of the world.
For a Silver Circle Diseased to advance further was several, even dozens, of times more difficult than all their previous advancements combined.
Only the truly outstanding could obtain "qualification" and ascend the steps connected to the core of the Focus of Infection. Reaching the end of those steps meant arriving at the deepest part of the world, at the source of all plagues.
There, the Sick One would complete the final and most primordial "Origin Gene," which was connected to the origin of the world.
Their bodily affliction would undergo unprecedented, thorough development. They might even obtain gene expression capable of manipulating and influencing the rules of the world to a certain extent. This was why a Plague Lord could not be shaken by native individuals.
Only the arrival of forces from beyond the world had broken the original order of the Plague Lords.
The so-called "qualification" was not so much the qualification to become a Plague Lord as it