I was hoping that Flynn scaring the emperor and sparing his life would scare off any attempts of his to go after him and his friends. But no, this proves that sparing him was a stupid move and he should've but the bastard's head on a spike.
Either this will end up as a tragedy, or the demi humans and beasts managed to win and flee the Empire, so the Romans decided to do some good ol' historical negationism and claim that they were exterminated to avoid shame.
@Tersione This is a recurring theme on whatever manga Masasumi Kakizaki is doing: Spineless weaklings with certain amount of authority swearing revenge after being spared by our manly heroes. Green Blood and that Rainbow manga had this concept on spades.