A plotline could involve Sombra's spirit lingering after his defeat. Luna, being attuned to the more mysterious aspects of Equestria, detects this. She tries to communicate with his spirit to learn more about his motives. This could lead to a journey of self - discovery for both of them as they explore Sombra's past and Luna's role in understanding the darkness within Equestria.
In a fanfiction, Sombra could be resurrected in a different form. Luna is the first to encounter him. Instead of immediately attacking, she decides to hear him out. Sombra claims he has changed and wants to make amends. Together, they embark on a quest to prove his new - found goodness to the other ponies of Equestria, facing many challenges along the way.
Another plotline could be a time - travel story. Twilight accidentally travels back in time to when Sombra was first becoming evil. She tries to change his path and prevent him from turning into the dark villain he became. This would involve her getting to know the younger Sombra and trying to influence his decisions with her knowledge of the future.
One idea could be a story where Luna and Sombra meet in a dream realm. Luna, being the princess of the night, has the power to traverse dreams. Sombra, once a powerful and dark figure, could be lost in this dream realm. Luna tries to understand his past and help him find redemption. It could explore themes of forgiveness and the power of understanding.
One possible plotline could be Luna seeing Twilight's potential and taking her under her wing to teach her some ancient and forgotten magic. This would lead to Twilight having unique abilities and a special bond with Luna.
One possible plotline could be that Luna sacrifices herself to save Equestria from a powerful and ancient evil. She might use all of her magic and strength to defeat the foe, but in the process, it drains her life force completely.
A plotline might involve Luna seeing Scootaloo's potential and deciding to adopt her as a sort of protege. This could lead to Scootaloo learning about Luna's powers and responsibilities in Equestria. For example, Luna could take Scootaloo on nightly adventures to teach her about the magic of the night. Along the way, Scootaloo could also help Luna reconnect with the ponies who might still be a bit wary of her due to her past. It could be a story of growth and friendship for both of them.
A common and interesting plotline is Sombra's redemption. Twilight often plays a key role in this, like in 'Sombra's Redemption' where she helps him see the error of his ways. Another is their teamwork. In 'Twilight and Sombra: Against the Dark Forces', they team up to fight a greater evil that neither could face alone. It shows how their different powers can complement each other.
In terms of the plot, it could start with Sombra's return or some sort of threat that he poses. Luna then steps in to deal with it. The setting within the My Little Pony world would be important. It could be set in Canterlot or some other location. The fanfic might also introduce new characters or use existing ones to support the main plotline between Luna and Sombra.
One common theme could be the battle between light and dark. Luna represents the moon and has an association with the night, which can be seen as a time of mystery and sometimes danger. King Sombra is a dark character. So the fanfic may explore this contrast in terms of their powers and personalities.
Well, one possible plot could be that they start as enemies as in the original lore. But then, an external threat forces them to work together. They gradually learn about each other's pasts and find some common ground. Maybe they both had difficult upbringings in different ways. And in the end, they form an unlikely alliance that changes the power dynamics in Equestria.
One possible plotline could be that Luna and Hermione are studying together in the Hogwarts library late at night. They start discussing their different views on magic and life, and as they get closer in their conversation, an unexpected moment of closeness leads to a kiss. It could be a spontaneous expression of their new - found understanding and connection.