Ethel (A Stitch in Time)

Ethel was a Time Weaver. She was at constant odds with her sister Gretel, as she and her other sister would constantly try to rip apart the fabric of the universe, which Gretel would always repair.

When the Twelfth Doctor accidentally landed on her unnamed sister, she tried to get revenge by sending time flies at him and Clara Oswald, as well as his past incarnations. She was defeated when the Doctor teamed up with Gretel and sent the time flies to attack Ethel instead of him. (COMIC: A Stitch in Time)

The Twelfth Doctor later told Jennifer Fletcher that "Ethel" was the nickname of the Vigilant Eremites of the Andurax. (COMIC: Ghost Stories)