In an interesting fanfiction plot, Cersei's son could be exiled from King's Landing. During his exile, he forms a band of outcasts. Together, they build a new community away from the power struggles of the capital. As he grows, he realizes that his mother's way of ruling is wrong. Eventually, he returns to King's Landing with his new - found wisdom and tries to overthrow his mother's tyrannical rule, not to take over but to establish a more democratic and fair system for the people of Westeros.
Perhaps Cersei's son, having grown up seeing the chaos his mother caused, could bring about a new form of governance. Instead of the feudal system that was prevalent, he could introduce a more democratic - like system where the voices of the lords and the common folk are heard. This would be a huge change from the power - hungry struggles that were characteristic of the Game of Thrones world.
Perhaps in the fanfiction, Cersei's son discovers a hidden power within himself. He uses this power not for domination like his mother would, but to heal the broken kingdom. He might travel across the land, learning from the common people and using his new - found abilities to bring prosperity.
He could influence events by being a voice of reason in Cersei's court. If he's intelligent and perceptive, he might be able to persuade his mother to make more diplomatic decisions rather than always resorting to force.
One possible plotline could be Cersei's son growing up to be a more benevolent ruler than his mother. He could see the destruction she has caused and try to make amends. Maybe he forms alliances with former enemies to bring peace to the Seven Kingdoms.
One possible plot could be that their son discovers the truth about his parents' tumultuous relationship. He might struggle with the knowledge that his mother had affairs and his father was not the ideal man he seemed. This could lead him on a journey of self - discovery, trying to figure out his place in the Seven Kingdoms.
In some fanfiction, Jaime's character might develop into a more remorseful figure. His relationship with Cersei could be a source of internal conflict, and he could start to question his loyalty to her more deeply, leading to a change in his actions and decisions.
Sansa Stark could be an interesting pairing. It could be a story of two strong - willed women from opposing sides. They could either become bitter enemies or, in a more creative take, find common ground and form an unexpected alliance. Also, Margaery Tyrell is a great character to pair with Cersei. Their power struggle in the show was fascinating, and fanfiction could take it in new directions, like Margaery actually befriending Cersei and showing her a different way to rule.
The son's character might develop as he uncovers family secrets. Knowing about his mother's true nature and his father's misdeeds could make him question his own identity. He could start as a naive young man, but as he digs deeper, he becomes more cynical. But instead of being consumed by it, he decides to break the cycle of corruption and lies that his family has been part of. He could start to develop his own moral code, different from the cut - throat ways of his parents.
One interesting plotline could be an alternate universe where Jaime decides to fully turn against Cersei much earlier. He might expose her secrets to save the realm from her tyranny, leading to a complex power struggle within King's Landing.