There was no clear connection between Sanguine Red's novels," Tengen " and " Tengen 1 ", which could form an independent series. However, judging from the name, Tengen could be considered a follow-up to Tengen 1 because Tengen was usually used to refer to the first work in the series. However, this was not absolute, because the name connection did not necessarily mean that there was a direct causality between the works.
Obviously, Naruto and Sasuke are going to be the main characters. Their relationship and how it develops after their fight is likely to be the central focus of the fanfic.
One main element is his difficult upbringing in poverty - stricken surroundings. Another is the constant bullying and discrimination he endured due to his physical appearance. And of course, his strong bond with his sister Daki. This bond was what drove him to protect her at all costs and also influenced his actions as a demon. For example, he would go to great lengths to avenge any harm done to her because of their shared experiences of being outcasts in society.
Well, perhaps in the 'naruto vs sasuke the aftermath fanfic', there could be a focus on the physical and mental recovery of both Naruto and Sasuke. Naruto, being the more positive of the two, might bounce back quickly, but Sasuke's internal struggles could be explored in depth. There could also be new threats emerging that they have to face together, which would force them to put aside their differences and cooperate, even if reluctantly at first.