What makes a good mare become a monster? More often than not, it is a slow progression of many decisions and unfortunate events over a long period of time. Nightmare Moon is one of the most powerful and feared beings in Equine history, but what ultimately caused Princess Luna to embrace the darkness and try to blot out all light with eternal night?
This is an appendix to A Journey Unthought of: A man's life in Equestria, however it can be treated as its own separate story that enhances the established canon of My Little Pony: Friendship is Magic. This story was written before the Season 4 Premiere took place.