One possible reason could be a misunderstanding. Maybe Naruto was misidentified as a threat in a tense situation. For example, if there was some sort of dark jutsu at play that clouded Kurenai's judgment and made Naruto seem like an enemy. Another reason might be that Kurenai was under some sort of mind - control. There are many villains in the Naruto universe who are capable of such things. If she was being controlled, she might unknowingly attack Naruto.
He might be shocked at first. Naruto is used to seeing Kurenai as an ally, so being hurt by her would be unexpected. He could immediately ask her why she did it. If it was a serious injury, he might struggle to stay conscious while trying to understand the situation.
There could be many interpretations in such a fanfiction. Maybe it shows Naruto's vulnerability in relationships. It might be a way to explore his character deeper by putting him in a difficult emotional situation.
There could be. Fanfiction is a vast world where all kinds of scenarios are explored. But it's not something that is part of the official Naruto storyline. You can try searching on popular fanfiction websites like FanFiction.net or Archive of Our Own. Just keep in mind that the content may be quite different from what you expect based on the original series, and it may also not be appropriate in some ways.
Naruto might be initially shocked and heartbroken. He is someone who values loyalty and friendship deeply, so being cheated on would be a huge blow to him.
One possible plot could be that Naruto finally experiences a motherly figure in his life. Kurenai, being a skilled ninja, could train Naruto in different ways, especially in genjutsu which she is good at. Naruto might grow to be more well - rounded in his skills. Also, he could have a more stable home environment, which would boost his self - confidence and help him make better relationships with his peers.
Maybe Naruto is trapped in a dangerous place, like a collapsing cave during a mission. Anko, with her quick thinking and combat skills, and Kurenai, who is very strategic, find him. Anko could break through any physical barriers in the cave, and Kurenai would use her genjutsu to keep Naruto calm so he doesn't panic and make the situation worse. Together, they get him out of there.
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.
One possible storyline could be that in a mission gone wrong, Kurenai accidentally uses a jutsu that ends up hurting Naruto. Maybe she misjudges the situation and her genjutsu affects Naruto in an unexpected and harmful way.
Sakura would probably be very angry at Kurenai. She's protective of Naruto and would demand an explanation. She might even try to heal Naruto right away if it was a physical injury.