A young girl's greatest fear isn't monsters. It isn't evil. It isn't even death. No, her greatest fear overshadows all of these.
Her greatest fear is to be alone.
The Dark Magical Girl is this fear personified, molded into a dark parody of the Magical Girl. Where the Magical Girl is a force for good and light, the Dark Magical Girl's virtues have all been twisted to serve evil.
Normal Magical [...] [tvtropes.org]