I wrote a short dnd campaign (4 or 5 sessions) with the main NPC who framed the adventure being a self important egomaniac, and the only world they saved was his world-sized ego. Making that NPC trusted by the players and breaking that trust by seeing the actual stakes of the adventure was a pretty neat idea, and it would have been a good start to my dming.

Unfortunately i ate the “save the world” pill and binned that idea for a shitty campaign about saving the world and it died the classic death of all campaigns: scheduling.

I think I might eventually run that game when I get back into DMing or start with a new group.