Summoned as the Demon King: Modern Magic Land?

Sisson is summoned to Norad by the goddess Lorraine: the demon king is dead, the royal power is in debt, the aftermath of the stock market crash is still lingering, the Lanles Summit is close at hand, and even the demon clan has "disintegrated". How can a demon king with nothing revive the demon clan? There is no unparalleled slashing - accounting, deterrence, trading: black market and bank, nobility and legion, miraculous weapon and church, imperial succession war and abyssal intelligence. Who wants to talk? Who wants to fight? When demons, humans, elves, vampires, dragons, and abyss look at the mainland at the same time ——"In this era, do we still need a demon king?"