In an unexpected development, Princess Luna has informed me that should things carry on as they have been and for her own personal reasons, the persona that created Nightmare Moon's form may return for revenge. In this storyline, Discord was able to infect Luna with his magic before he was sealed by her and Luna, and that infection ate away at her mind until it drove her mad from jealousy of Celestia's love and praise.

That persona took hold after Discord unveiled that a mare that had been treating her with kindness was in fact a creation of Penny Feather, a mare allied with the deity. This was the final push that sent Luna over the edge. She reappeared as Nightmare Moon after the dark persona took over once again.

Originally introduced as a spoof character, "Gamer Luna" was put into a spell by Discord that made her play the games he supplied while he was free to torture Equestria. However when he called back his magic to increase his power, the spell was removed and Discord decided to start attacking Luna's mind with her darker personality...