Kakashi is known for his laid - back yet highly skilled nature. His influence on Naruto could be in terms of teaching him to be more strategic in battles. Rin, being kind - hearted and having a strong sense of care, would give Naruto the emotional support he lacks. So Naruto might become more balanced in his approach to life and ninja - hood.
In a fanfiction of Kakashi and Rin's love story, it could start with their time in the ninja academy. Rin was always drawn to Kakashi's natural talent and mysterious aura. Kakashi, on the other hand, was initially oblivious to Rin's feelings. One day, Rin got injured during a training session. Kakashi carried her all the way to the medical tent. That was the first time he realized how much she meant to him. As they grew older, their bond deepened, and they found themselves falling in love while on various missions.
In this fanfiction, perhaps the story could focus on how Kakashi and Rin's adoption of Naruto changes the relationships in the village. Naruto might not be as ostracized as he was in the original story. Also, they could help Naruto deal with the Nine - Tails inside him in a more gentle and effective way compared to what happened in the canon story.
It could be Orochimaru. He might be interested in the unborn child for some dark experiment, thinking that the child of Kakashi and Rin could possess some unique abilities. He could send his minions to spy on them or even try to kidnap Rin.
A more complex plot could be centered around any potential threats to Rin during her pregnancy. There could be enemies who see this as an opportunity to target them, so Kakashi has to be extra vigilant in protecting her. This could lead to some intense action scenes where Kakashi uses his Sharingan to fend off attackers while also ensuring Rin's safety.
The most romantic moment could be when Kakashi finally confesses his love to Rin. After years of hiding his feelings, he takes her to a secluded spot near a beautiful waterfall. The moonlight shines on them as he looks into her eyes and tells her how much she means to him.
Saber is often a symbol of honor and power, and in relation to Rin, they can be written in fanfiction as two characters who grow to understand and respect each other more. Rin's knowledge of magic can be a key factor in their interactions. However, when it comes to lemon fanfiction, it's not a proper area to explore their true characters as it usually involves vulgar content.
Often, Gai is paired with Kakashi in Hurt Kakashi fanfiction. Gai, with his unwavering belief in friendship and his eternal rivalry with Kakashi, can be a great character to interact with a hurt Kakashi. He might try to pull Kakashi out of his slump through their friendly competition. Also, Rin is sometimes included. Since she has a significant past with Kakashi, her presence in the fanfiction can either be a source of comfort or more pain, depending on how the story is written.
One effective way is to show Rin's loss of interest in things he used to enjoy. For instance, if he used to love training or cooking, suddenly he has no enthusiasm for it. His appearance can also change. He might look disheveled, with messy hair and dark circles under his eyes. Writers can also use flashbacks to his happier times and then contrast them with his current depressed state. By showing how much he has changed, it emphasizes the depth of his depression. And his reactions to small things can be exaggerated. A minor setback might make him feel completely defeated, which is a sign of his fragile mental state.