In a fanfiction, Kakashi's past in ANBU could be the backdrop for a story where Sakura is on a mission and gets in over her head. Kakashi, using his past experiences and skills from the ANBU days, comes to her rescue. This could lead to a deepening of their relationship as he imparts some of his hard - earned wisdom to her.
Kakashi's abilities would likely be enhanced in the past. He has all the knowledge and skills he's gained in the future. So, his combat skills would be more refined. His Sharingan would be even more powerful as he would know better how to use it. He might also be able to teach his younger self some new jutsu that he learned over the years.
In this fanfiction, it could also be about Naruto going back in time to learn from Kakashi. Since Kakashi was a great ninja in the past, Naruto might want to gain some skills or wisdom that he didn't have the chance to learn before. They could form a unique bond during this time, different from their relationship in Naruto's original timeline. Kakashi could be initially suspicious of this strange Naruto from the future but gradually come to trust and mentor him.
The plot could involve Sakura finding a mysterious artifact related to Kakashi's ANBU days. As she tries to figure out its significance, she has to seek Kakashi's help. This brings them closer as they explore the secrets of his past together.
The theme of friendship is also prevalent. Despite the time difference, they form a strong bond. They might start off as strangers, but as they work together towards a common goal, their friendship deepens. In some fanfictions, this friendship could even change the entire Naruto universe's future. Additionally, the theme of self - discovery is often explored. Naruto may learn more about his own roots and past through his interactions with Kakashi, and Kakashi may discover new aspects of himself with Naruto's influence.
One idea for this 'Past Kakashi Meets Future Obito' fanfiction could be that their meeting is not a coincidence. Maybe it's part of a grand plan by some mysterious force. When they meet, past Kakashi would be in awe of future Obito's power and skills. Future Obito, though, would see the innocence still in past Kakashi. They could end up training together, with future Obito teaching past Kakashi some new jutsu. And as they bond, they might rewrite their fates and change the future of the ninja world for the better.
One possible plot twist could be that Naruto's love for Kakashi from the past disrupts the timeline. Maybe his feelings cause him to unknowingly change events that were supposed to happen. For example, he might prevent Kakashi from making a certain decision that was crucial in the original timeline.
It could develop in a really interesting way. Since Naruto is from the future, he might have knowledge that he uses to protect Kakashi. This would make Kakashi curious about Naruto. As they interact more, they could start to develop a deep bond. Naruto might share some of his future experiences with Kakashi in a veiled way, and Kakashi would start to see Naruto in a different light, leading to a relationship that is based on mutual respect and a bit of mystery.
In the past, their relationship could be more complex. Kakashi might be suspicious of Naruto's sudden appearance and his knowledge from the future. Naruto would have to prove himself to Kakashi. However, as they work towards a common goal, like saving Konoha from a threat in the past, they would gradually build trust. Their relationship could also change in terms of how they interact with others in the past. For example, they would need to pretend to be normal villagers or ninjas from that time, and this new situation would impact how they relate to each other.
If they travel to the past, Kakashi might see Sakura in a new light. In their original time, he saw her as a student, but in the past, she could show different skills and a more mature side, which could make him respect her more as an equal. Their relationship could become more of a partnership rather than a teacher - student dynamic.