Demon King Reemployment: The Dean Teaches Me to Destroy the World

I, the most flirtatious Dark Lord in history, am also the gold-medal lecturer of a dragon-slaying cram school on the side. After being ganged up on by the hero and having my soul transmigrated, I open my eyes to find myself as an F-rank trash runt at the most exhausting academy in the magic-civilization world. Just as I prepare to keep a low profile and pretend to be dead to survive, the whole-school broadcast suddenly announces in a passionate voice: "Congratulations to this student for activating the hidden quest—heir to the legacy of the ultimate villain!"

Before I can laugh three times, the legendary holy knight principal who once sealed me pushes the door open and walks in, eyes blazing as he pulls out a lesson plan: "First, I'll teach you how to elegantly destroy the world—"

I: "...Wait, does villain training this season have to be this hardcore?"