One big hint was a brief half a second shot of her shadow in the post credits scene of the first film.
She's been known as one of Disney's most evil villains, as unlike most, actually plans on taking over the universe and recreating as her own whilst killing many innocent people, destroying precious belongings, colliding stars with planets and bringing evil to Weird World all just for fun.
She's the oldest Disney Villain, beating out Hades and Bill Cipher.
She's also very likely the oldest Disney character to date.
She confirms she doesn't have parents and was formed out of nowhere by water, stardust and black magic.