Friendship is a very common theme. Since Twilight and Luna are both important characters in MLP, their friendship is often explored, like how they support each other through different challenges.
One popular mlp twilight x luna fanfiction is 'Twilight's Lunar Bond'. It beautifully explores their relationship in a friendship - centered story. The characters are well - written and the plot is engaging.
The main characters are clearly Luna and Twilight. Luna, being the one who adopts Twilight, is likely to play a guiding and protective role. Twilight, on the other hand, is the one being adopted and will probably experience growth and development under Luna's care.
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.
Another theme is self - discovery. The OC usually has some sort of journey where they learn more about themselves, and Luna also often discovers new aspects of her personality or her role in Equestria through her interactions with the OC. For example, in some fanfictions, Luna realizes she can be more approachable through her time with the OC.
One common theme is friendship. Given that they are two characters in the MLP world, their relationship often showcases the power of friendship. Another theme is magic, as both characters are associated with celestial and magical elements in the MLP lore.
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 common theme is redemption. Since Tempest has a more troubled past, many fanfictions focus on her journey towards redemption with Twilight's help. Another theme is friendship. They are two very different characters, so exploring how they become friends is popular. For example, they might start off as strangers or even enemies and then develop a deep bond.
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.
Another theme is friendship. Just like in the original My Little Pony series, Twilight forms a bond with the human character. They support each other through various challenges, whether it's Twilight helping the human understand a magical problem or the human helping Twilight with a non - magical issue in their world.