As you know, we never delete anything. Ever. For a universe, what you can do is flag it for moderator review, and then we can flag it as Closed or Completed. Completed roleplays move to the Library where people can marvel at your awesomeness, while closed universes merely have their content hidden from the public. Usually this is done in cases of people looking for smut or if a spambot gets into the universe creation system.
Characters are a bit trickier than that. Since characters are contained in the universe they were created in, the most you can do is wipe the profile of everything but their name and avatar, abandon the character, and not leave it up for adoption by someone else, but anyone with the link to their profile can still read their activity. (You can upload a black square for their avatar if you so choose. I know someone that took this option for characters they didn't want to use anymore.) Also note that if you submit a character to a universe that requires GM approval and it gets rejected, you still have it show up in your roster.
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