His character could develop in terms of his relationships. He might start to value loyalty and honesty more, especially in his friendships and marriages. This could lead to him making different choices in who he surrounds himself with. For example, he may choose to have more true friends rather than just political allies.
Perhaps a plot point could involve his relationships. If he is reborn, he may handle his marriage to Cersei Lannister differently. He could try to build a more genuine relationship with her or find a way to avoid the animosity that was there before. This would have a huge impact on the political and family dynamics in Westeros.
Perhaps their relationship begins with curiosity. Daenerys has heard of the powerful Robert in Westeros, and Robert is intrigued by this Targaryen with a claim to the Iron Throne. As they communicate more, they find common ground in their desire for a just Westeros. They might start to fall in love slowly as they share their dreams and fears, and work towards building a better future for the Seven Kingdoms.
Good fanfiction about Robert Baratheon also needs to capture the essence of the world he lives in. It should include the political intrigue, the power struggles, and the cultural aspects of Westeros. If it can tie in his actions as king with the greater political landscape, like how his decisions affected the different houses, it makes for a great read. Also, delving into his vices, like his drinking problem, and how it impacts his rule and those around him is a plus.
One idea could be a story where Robert Baratheon discovers Jon Snow's true parentage earlier. This could lead to a complex relationship where he sees Jon as a potential heir or a powerful ally. He might take Jon under his wing, train him in the ways of leadership and warfare, much like he did with Ned Stark's other children.
Power is a common theme. Fanfictions often explore how Robert wields his power as king, whether he uses it wisely or misuses it. Another theme is love and lust, like his relationship with Cersei and how that affected his rule.
One aspect to consider in this fanfiction could be the clash of cultures between the Baratheon and Stark families. Since Robert is a Baratheon and the OC is a Stark, their relationship might be shaped by the different values and traditions each family holds. For example, the Starks are known for their loyalty and honor, while the Baratheons can be more power - hungry. This could create interesting dynamics in the story, such as how they handle political situations together or how they resolve conflicts that arise from their family differences.
One possible fanfiction could start with Robert Baratheon as a young man. He is full of ambition and dreams of a united Westeros under his rule. He trains hard in combat, his sword becoming an extension of himself. He meets his future friends, like Ned Stark, during these formative years. They share tales around the campfire and make grand plans for the future. As he grows older, he participates in battles, his victories making him more and more renowned. His charisma draws people to him, and soon he is seen as a natural leader. But with power also comes temptation, and he has to face the challenges of politics and intrigue that come his way.
Finding good 'Robert Baratheon and Daenerys lemon fanfiction' can be quite a challenge. First of all, the combination of these two characters is not a common one in the mainstream fanfiction community. However, if you search through some of the more niche or adult - themed fanfiction sites, you might come across some. But be aware that the quality can vary greatly. Some might focus too much on the 'lemon' aspect and lack in plot or character development.