The theme of power dynamics is often seen in Discord x Celestia fanfic. Celestia is a powerful alicorn princess, and Discord has his chaotic magic. Fanfics play with how these two powers interact and balance each other. Also, the theme of forgiveness is common. Celestia has to forgive Discord for his past misdeeds, and fanfics explore the journey towards that forgiveness in different ways. Some fanfics also have a theme of discovery, where they discover new things about each other and themselves through their interactions.
In Discord x Celestia fanfic, a recurring theme is the exploration of their past. Writers often dig into what their relationship was like before Discord's chaos and his subsequent imprisonment. Another theme is the concept of change. How Discord changes after his reformation and how that affects his relationship with Celestia. There are also fanfics that focus on the theme of trust. Given their history, building trust between them is a significant part of many stories. These themes add depth and complexity to the fan - created relationships between Discord and Celestia.
One common theme is the idea of redemption. Discord has a past of causing chaos, and in many fanfics, his relationship with Celestia is part of his journey towards redemption. For example, Celestia may offer him a chance to prove himself and do good for Equestria.
One common theme is sisterly love and reconciliation. Since they are sisters in the original concept, many fanfics explore how they strengthen their bond.
A theme of redemption can sometimes be present. Maybe one of them has made mistakes in the past, and through their relationship with the other, they find a way to make up for those mistakes. Or perhaps they are both trying to redeem themselves in some way, and their bond helps them in this journey. Additionally, a theme of mystery could be involved, where they are trying to solve a mystery together, which deepens their connection.
One common theme is the power struggle. Given Celestia's role as a powerful ruler of light and Sombra's association with darkness and power, many fanfics explore how they deal with their different levels of power. For example, in some, they have to find a balance between their powers to achieve a common goal.
One popular Discord x Celestia fanfic is 'The Celestia - Discord Alliance'. It shows an interesting take on how their relationship could develop in an alternate universe. There are also some fanfics that explore their interactions during a time of crisis in Equestria. For example, 'When Discord and Celestia Face the Dark Magic'.
Well, the plot could involve Celestia and Discord having to team up to save Equestria from a new, unknown threat. Maybe a powerful dark magic that neither of them can handle alone.
One common theme could be friendship. Luna and Celestia are sisters in many interpretations, so fanfics might explore their sisterly bond, how they support each other through difficult times. Another theme could be power and responsibility. Since they both have important roles in their fictional world, stories could be about how they manage their powers and the responsibilities that come with them.
A common theme is sisterhood. Given their relationship as sisters, many fanfics explore the deep bond between them, including how they rely on each other and support one another in ruling Equestria.
Create an interesting plot. It could be a conflict between order (represented by Celestia) and chaos (represented by Discord). Or it could be a story where they have to cooperate against a common enemy. Make sure the plot has a clear beginning, middle, and end. For example, start with Discord causing some minor chaos in Canterlot, Celestia tries to stop him in her usual way but fails. Then a bigger threat emerges that forces them to work together. In the end, they either defeat the threat or find a new balance between order and chaos.
One common theme is mentorship. Celestia is often Twilight's mentor, so the fanfics explore how Celestia imparts knowledge and wisdom to Twilight. Another theme is friendship. Despite their different positions, they form a deep friendship which is often depicted. And power is also a theme, like how Twilight grows in power with Celestia's guidance.