Those who linger outside of cities are mutated in some way, forcing those who are unable to live in civilization to be cursed and marked.
Some cultists still keep away because they believe the Vex gives them power. The opposite of social distancing.
To keep the curse at bay, the races must mix their blood in a regularly performed ritual.
With the exception of the Guild dwarven drill submarines, the continent falls under a kind of quarantine, with trade comes to a standstill.
Maybe Corvax created the Vex of Ruin to pave the way for his next attack when he wakes back up?