When the Titans invaded Earth before, humanity also experienced a parasitic crisis.
Back then, Mu You managed to overcome the crisis by having all suspected hosts die once, and then reviving everyone with Miracle Divine Power.
But now? The Barbarians cannot be resurrected, so how can we ensure that the Barbarians aren't wiped out while rooting out the infiltrators among them?
Even if we can identify those who are overt parasites, there's bound to be many hidden spies in the background. As long as these parasites don't act or reveal themselves, they will never be discovered.
Until one day, these spies strike at some critical moment, causing significant damage easily. There's nothing more troublesome than having enemies hidden among your own people.
Mu You suddenly realized that it's no longer a matter of convincing the Barbarians to unite, but whether they dare to collaborate with the Barbarians anymore…