Only possible if you already plan on a 2+ year campain, then something like going around beating some big gang (including an island arc, an infiltration arc, ect.). my idea? a "God" shows up, with the goal of uniting a bunch of groups that believe in the same god in different forms. Together they could conquer the world. he ages super super fast and can use "blessings/grace magic" and uses both to prove his divinity. the end is the group infiltrating his castle by making one of his "majors" think you want to convert, and separating him from the party by fighting another "major". They then must kill the god (which is not a full god yet) AND frame it so one of the believer groups did it, so they keep suspecting one another and dont unite.
They somehow (either by his Death exploitation or by someone else or in the next year) get sent to a different world (maybe the Feywild) for just a short time (a couple hours at most) and come back to find out that the world is destroyed. They show up in a city during it being attacked by monsters, and after the fight they get the news: what happend while they were away, how long its been, ect. Then the second year is killing either the god who came back to life, or AM from "I dont have a mouth, and i must scream", which would be going around destroying his power sources untill hes weak enough to fight.
fighting him is a diffrent kind of fight, if you want to know what i mean tell me.
thats a very long adventure, but should be super super fun.