A morality story can be written and make site acceptable creepypasta. Check out my story The Queen Of Sheba. That story is completely original and doesn't reference anybody's copyrighted material. It does use an authentic legend. If you want a futuristic "Outer Limits" back stab, cork screw and double dealing type of story of mine, try The Vaults of Eternal Bliss.
It's not the only story I have seen on the site that I would say fits the genre of morality tale. See Shadows on the Ice by Banned In CP, for example. Again, there is no reference to anything else.
The more stories I think of, the more come to mind. Filthy Pig by Jdeschene. La Bruja by Killahawke1.
If you want a framing character who throws down the divine lightning bolts to zap the evil ones, you must invent your own or pick one that it is so old it is not under any copyright. (Before 1900 is safe, so you could use The Ghost of Christmas Future, for example.)
One piece of advice: Post your stories to the Writer's Workshop in the forum before going on the main Wiki.