There are several key characters in the My Little Pony Nightmare Moon story. Firstly, Twilight Sparkle, a magic - using pony with a thirst for knowledge. Her friends are crucial too. Pinkie Pie, the fun - loving and party - planning pony; Rainbow Dash, the fast - flying and brave one; Applejack, the hard - working and honest pony; Rarity, the fashionable and creative pony; Fluttershy, the shy but kind - hearted pony. And then there are Princess Celestia and Nightmare Moon (Princess Luna). Celestia has a connection to the whole situation as Luna's sister, and Nightmare Moon is the antagonist that the others must face.
In the My Little Pony Nightmare Moon story, Nightmare Moon was once Princess Luna who became jealous of her sister Celestia. This jealousy turned her into Nightmare Moon. She was banished to the moon for a thousand years. When she returned, she brought a night that would last forever. But the main ponies, like Twilight Sparkle and her friends, worked together to defeat her and turn her back into Princess Luna through the power of friendship.
There could be a fanfiction where Nightmare Moon teams up with the main ponies in an alternate universe. In this story, they realize that her power can be used for good when she is given a second chance. They work together to fight a greater evil that threatens all of Equestria.
Many fans like to create their own versions of Equestria in fanfictions. Nightmare Moon is a great character to use in these alternate universes. She can be the catalyst for change, a villain, or even a hero, and this flexibility makes fanfictions about her really interesting.
The relationships of Nightmare Rarity in fanfiction are also quite fascinating. She could have a complex relationship with Twilight Sparkle, for example. Maybe they were once friends but now are enemies because of Nightmare Rarity's new form. Fanfiction writers play with these dynamics to add depth to the story.
In a fanfic, their relationship could be developed by having Celestia make sacrifices for Nightmare Moon. This shows that she truly cares about her sister, even in her Nightmare Moon form. For instance, Celestia could give up some of her magic to try and heal Nightmare Moon. Nightmare Moon, in turn, might be initially suspicious but then start to question her own hatred towards Celestia. You can also have them interact with the other ponies in Equestria. Seeing how Celestia is loved by the ponies and how they fear Nightmare Moon can make Nightmare Moon re - evaluate her relationship with Celestia and Equestria as a whole.
I'm not entirely sure specifically which 'nightmare moon lemon fanfiction' you are referring to. 'Lemon' in fanfiction often implies some form of romantic or more adult - themed content. However, if we consider it in a general sense, it might be about exploring the character of Nightmare Moon in a more creative and perhaps unorthodox way within the fan - created narrative.
Nightmare Rarity is an interesting take in the My Little Pony world. In this story, Rarity is often transformed into a more menacing or 'nightmare' version. Usually, it's due to some dark magic or her own inner turmoil getting out of control. This new form of Rarity might have different powers and a more sinister look, which makes for a great plot device in the overall My Little Pony lore.
The 'mlp nightmare moon wins' fanfic could explore different character arcs. For example, Twilight Sparkle might have to face a greater challenge in her quest for knowledge and friendship. Other ponies would also be forced to adapt to a world where Nightmare Moon's will prevails, and their values might be put to the test.
Another theme is friendship. Despite the differences between Twilight and the threat associated with Nightmare, friendship usually plays a role. For example, Twilight might rely on her friends' support to overcome the challenges related to Nightmare. This theme is in line with the overall My Little Pony concept.