Talk:Starlight Glimmer/@comment-1276314-20160329195457/@comment-1031724-20160401051210

In the show, Luna became corrupted by the bitterness in her heart (possibly magnified by Sombra before she banished him) and became Nightmare Moon. Mane 6 purified her, then she created the Tantabus to punish herself for what she did when she was Nightmare Moon

In the comics, the Nightmare Force originated from the moon and convinced Luna to let her possess her, becoming Nightmare Moon. Nightmare Moon was killed by the Mane 6, but was revived by the moon cycle, corrupted Larry and his people, possessed Rarity, and was killed by Spike.

So going by the comics, Nightmare is dead. Otherwise, if there was a force besides Sombra involved, it could magnify some darkness inside Starlight, except she's already in the reformed and remorseful stage