Naruto could use his Uzumaki bloodline's chakra reserves. He might overwhelm Might Guy with a large number of shadow clones, confusing him and creating an opening to save Tenten.
First, Naruto might try to reason with Might Guy. Since they are all comrades in the village. But if that doesn't work, he would rely on his ninja training. He has learned a variety of jutsus over the years. He could use his Transformation Jutsu to disguise himself as someone Mighty Guy respects, like Kakashi. This would give him a moment of hesitation from Guy. Then, he could use his Body Flicker Technique to quickly reach Tenten and whisk her away to safety.
Well, perhaps in this fanfiction, Might Guy is possessed by some sort of dark force. This makes him turn on Tenten during a sparring session. Naruto, being the hero he is, arrives just in time. He first tries to talk to Guy, but when that fails, he uses his speed and agility, skills he's honed over years of fighting. He quickly grabs Tenten and gets her to safety, then he has to figure out how to free Guy from the dark influence.
Maybe Naruto uses his shadow clone jutsu to distract Might Guy while he rushes in to grab Tenten and get her to safety.
It could be that Might Guy is under some sort of mind - control. So, without his normal self - control, he attacks Tenten, making it necessary for Naruto to save her.
His relationships would also develop. By protecting Tenten, he would earn her trust and respect. This could lead to a stronger bond between them and also with other members of their ninja group. Naruto might also gain a new perspective on Guy Sensei, understanding that even strong and respected teachers can be vulnerable to certain influences. He would learn to look beyond the surface and be more empathetic towards others.
Well, Naruto has his Nine - Tails chakra. He could potentially tap into that power to either overpower Might Guy or create some kind of shield around Tenten. He might also use his Rasengan, but in a non - lethal way to stop Might Guy's attacks long enough to protect Tenten. Also, Naruto is known for his quick thinking and adaptability in battle, so he could come up with a unique strategy on the spot depending on the situation.
Perhaps in the fanfiction, there's a misunderstanding. Guy Sensei thinks Tenten has stolen a valuable jutsu scroll or something important to him. Naruto, knowing Tenten is innocent, stands in front of her. He might try to reason with Guy Sensei first, using his charm and quick - thinking. If that doesn't work, he'll be ready to fight, using his Rasengan if necessary.
Naruto might be really confused at first. He's used to people being friendly or having normal crushes, but a yandere is a whole different level. He'd probably try to talk to her and understand why she's acting so strangely.
Well, for instance, Naruto could meet Brian the dog. Brian, being intelligent, could have deep conversations with Naruto about their different worlds and values. Naruto could share his dreams of becoming Hokage and Brian could talk about his writing aspirations. It would be an interesting exchange of ideas between a ninja and a talking dog.
Their relationship could start with mutual respect. Naruto respects Tenten's dedication to her weapon - based ninjutsu, and Tenten respects Naruto's strength and determination. They might start training together more often, which would lead to them spending a lot of time together. This time together would allow them to open up to each other about their pasts, their fears, and their hopes for the future. As they grow closer, they would start to develop feelings for each other, and these feelings would eventually lead to their marriage.
Naruto could use his shadow clone jutsu to create distractions. While Gai is busy dealing with the clones, Naruto can quickly get Tenten to a safe place.