Liliana Norfolk is the villainess.
However, not knowing how to behave like a proper villain, she stands alone at the gates of the Demon King’s castle.
Liliana: “Could you please teach me the ultimate villainous move?”
Demon King: “Well…”
And so, Liliana embarks on the pursuit of evil alongside the Demon King, who possesses the forms of both a dragon and a human.
All of this is in her quest to become the ultimate villainess.