Melefescent

Melefescent was a Great Old One identified by Rassilon. (PROSE: Divided Loyalties)

Behind the scenes
Melefescent is a thinly-veiled allusion to Maleficent, an evil, demonic faerie dubbed the Mistress of All Evil, who appears in the 1959 Disney animated adaptation of the fairy tale Sleeping Beauty. It is unclear if Melefescent is a parallel, N-Space counterpart to the "prime" Maleficent, or if the suggestion is that the original Maleficent, at some point after her various appearances in Disney media, was one of the powerful beings from other universes who made their way into N-Space and were dubbed Great Old Ones.

A version of the general, public-domain "" of made a cameo in the Thirteenth Doctor story It's Behind You!, drawn as similar (though not identical) to the Disney Maleficent. She was not identified by name.