Typically, in 'Simba x Kovu' yaoi fanfic, there would be a strong focus on the relationship between Simba and Kovu. It might explore their emotional connection in a more romantic or sexual way that goes beyond the normal platonic or rivalrous relationship seen in the original Lion King story. There could be a lot of character development specifically centered around their feelings for each other.
One characteristic could be the alteration of the power dynamics between the two characters. In the original context, they have a complex relationship related to leadership and territory. In yaoi fanfic, this might be transformed into a different kind of power play within their romantic relationship. For example, one character may be more dominant or submissive in the relationship, which adds an extra layer of complexity to their interactions. Also, the fanfic may often include detailed descriptions of their physical and emotional attraction, perhaps through vivid descriptions of their glances, touches, and internal thoughts about each other.
In 'Simba x Kovu' yaoi fanfic, the setting and background from The Lion King are usually incorporated but tweaked to fit the romantic storyline. There may be elements of the Pride Lands still being a central part of the story, but it could be used as a backdrop for their secret meetings or the development of their relationship. The fanfic might also play with the idea of how the other characters in The Lion King would react to their relationship, whether it be acceptance, shock, or even trying to break them apart. This can create a lot of drama and tension within the story, which is a common feature in yaoi fanfic in general.