It's possible that Kurenai tries to understand why Naruto is smoking. Maybe she discovers he's under some stress or going through a tough time. So instead of just scolding him, she could offer to help him deal with his problems in a more positive way, like suggesting training or meditation to relieve stress rather than relying on smoking.
One consequence could be that Kurenai reports Naruto to someone in authority, like Iruka or Kakashi. They might then have a serious talk with Naruto about setting a good example for the younger ninjas. Also, it could potentially damage Naruto's reputation among his peers, as smoking isn't really seen as a positive thing in the ninja world.
There are several possible reasons. For one, it could be a way to subvert the expectations of the Naruto character. In the original series, he's so pure and full of life. By having him smoke in fanfiction, writers can create a contrast. It might also be used to set a certain mood, like a gritty or more adult - oriented atmosphere. Additionally, it could be a symbol of his rebellion or a sign of him breaking away from the norms of his ninja village. Writers might use it to explore a different side of Naruto that wasn't shown in the original story.
One potential consequence is that it could cause a stir among more traditional fans. Since it goes against the established relationships in the Naruto series, some fans might be offended. They might see it as disrespectful to the original story and characters.
Family. It could focus on how Naruto and Kurenai form a new family with the baby. They learn about parenting, love, and sacrifice.
His reputation in the ninja world could be damaged. If Padme spreads false information or reveals his secrets, other ninja might view Naruto differently. They could see him as a liability or a threat. This could lead to him being isolated in the ninja community, and he might have to fight harder to prove himself again.
One possible consequence could be that Naruto is ostracized by some in the ninja world. Since controlling blood is a rather strange and perhaps 'creepy' ability to some, they might view him with suspicion or fear. This could lead to him having to prove himself more often in battles and interactions.
It could be related to their different personalities. Naruto is very outgoing and impulsive, while Kurenai is more calm and reserved. In the fanfiction, their clashing personalities might lead to Naruto developing a dislike for her. Naruto might feel that Kurenai is too strict or unapproachable, which causes him to hate her.
One possible plot could be that Kid Naruto gets lost in the forest and Kurenai, while on a mission, stumbles upon him. She decides to help him find his way back home. Along the way, Naruto shares his dreams of becoming Hokage with Kurenai, and she encourages him, seeing his determination.
One possible storyline could be a story of friendship and alliance. Maybe Naruto and Kurenai team up with an Akatsuki sister who has a change of heart. They could fight against the more evil elements within the Akatsuki together.
One possible plot development is that Naruto gets to experience a different kind of family dynamic. Kurenai could introduce him to her friends in the village, expanding his social circle. This could help Naruto feel more integrated into the village community.
One reason could be for the sake of creating drama. Fanfiction writers like to add intense emotions and conflicts to their stories. By having Kurenai cheat on Naruto, it creates a huge emotional upheaval for Naruto's character, which can lead to interesting character development arcs within the fan - created story. It also gives the writer a chance to explore how Naruto would react in such a difficult situation, which might be different from his usual optimistic and determined self in the original series.