As was once said, bad news travels around the world before good news tied its shoes.
It took longer than it did previously, due to the collapse of the Internet (along with the destruction of civilization world-wide), but the host of demons--as the survivors could no longer afford to delude themselves otherwise--and the thralls of men who either willingly turned traitor or got enslaved by them ranged further afield to finish the job they ran into resistance. At first this was effectively only against the thralls, as the demons remained immune to what the survivors could employ against them, but those thralls revealed the truth of Lord Cygnus' transformation into a demonic draconian- and installation as the king of this world.
As for the demons, they saw the subjugation of this world--as with many others--as sport, not war, and laughed as they slaughtered the resistance fighters with aplomb in the months immediately after their victory. Then word came that some survivors killed a minor demon by ambush. Then they ambushed a group and wiped them out. Then another survived an ambush and reported that some of them have learned how to use their powers, and they are adapting that knowledge to their own use. Then a major demon died in single combat against an empowered survivor, and Lord Cygnus could not let this be handled by underlings alone any longer.
Lord Cygnus, long an underdog accustomed to guerilla warfare, immediately upbraided his underlings for their incompetence. He analyzed their reports, told them where they went wrong (and why), and briefed them on how to handle the matter. This would have gone badly, had Lord Cygnus not whipped them into line with his iron will beating them into submission.
Meanwhile, the survivors began linking up in a recreation of the Internet of old. No sooner did this happen than some of the black humor returned and turned its barbs against the traitor-master. Knowing that Lord Cygnus was now a humanoid dragon, they began to mock him as "Trogdor the Burninator", and this mockery slipped into the slave pens where some people were allowed to live to satisfy the demands of their demon overlords. When this reached Cygnus, he embraced it.
"Very well then. If they mock me so, then I shall show them the terror in their object of scorn and be the very scourge that they proclaim. Fools!"