In the fanfiction, their characters could develop in relation to each other. For example, Twilight Sparkle's studious nature could rub off on Flash Sentry, making him more interested in learning. On the other hand, Flash Sentry's adventurous spirit could encourage Twilight to take more risks and step out of her comfort zone. This mutual influence could lead to a more well - rounded development of both characters as the story progresses.
Twilight's personality could also develop in terms of her social skills. Since having a baby means more social interactions with other ponies bringing gifts and advice, she could learn to be more patient and gracious. Flash Sentry could become more nurturing. He might learn to sing lullabies or tell bedtime stories, which is a new side to his usually tough - guard personality. This would show his growth as a character in the context of the baby fanfiction.
Perhaps it's a story about their friendship being tested. Flash Sentry gets an important mission that takes him far away from Ponyville. Twilight Sparkle is worried about him and has to deal with her own insecurities. In the end, their friendship prevails as Flash Sentry returns safely and they realize how much they mean to each other.
One common theme is friendship. Just like in the main MLP series, their relationship could be centered around the idea of growing closer as friends. They might start as acquaintances and gradually become best friends who can rely on each other no matter what.
They might interact with Pinkie Pie in a really fun way. Pinkie Pie could throw a party for them when they achieve something great in the story, like saving the town from a flood. Flash Sentry would be a bit awkward at the party at first, while Twilight Sparkle would be more used to Pinkie's antics. Another character they could interact with is Spike. Spike could be jealous of Flash Sentry at first if there's a romantic angle between Flash and Twilight, but then they end up becoming friends.
One popular storyline could be Flash Sentry helping Twilight Sparkle adjust to some new situation in Equestria. For example, when a new magical threat emerges, Flash Sentry, with his courage and Twilight's vast magical knowledge, they team up to face it. Another could be a story about their friendship developing over time. Flash Sentry might initially be in awe of Twilight's magic, and as they spend more time together, they learn more about each other's strengths and weaknesses.
Another possibility is that the fanfic is set in a time of crisis. Flash Sentry and Twilight Sparkle are called upon to use their unique skills to save Equestria from a powerful enemy. Along the way, they face challenges that test their friendship and loyalty, and in the end, they emerge victorious and with a stronger bond.
There's a fanfic called 'Flash Sentry and Twilight's Friendship Trials'. In this, they face various challenges that test their friendship. It shows how they support each other through difficult times and grow as characters. The descriptions of their emotions are quite vivid, making it an engaging read.
The theme of magic also plays a big role. Given Twilight's strong connection to magic, fanfictions may show Flash Sentry being in awe of her magic or even having some sort of magical encounter himself because of her. Also, the theme of growth, both personal and in their relationship, is quite common. They start from being acquaintances and grow into a couple or very close friends over the course of the story.
One great aspect of Flash Sentry and Twilight Sparkle human fanfiction is the exploration of their relationship in a human context. It allows for new dynamics and character development. For example, in some fanfictions, Flash might be a popular jock in high school while Twilight is the nerdy but brilliant girl. Their interactions can range from initial misunderstandings to a deep connection as they discover each other's true selves.
Often, these fanfictions highlight the contrast between Twilight's intellectual and magical side and Flash Sentry's more physical and practical side. This contrast creates interesting interactions and relationship building.