Unnamed (as of now), is an ex-ninja of the hidden leaf, was friends with Kakashi at one point but grew apart when he got his team
Unnamed, became a hidden Leaf operative (the mask people) not long after graduating (Kakashi will always be the youngest to make it into there) she didn't know Kakashi was part of it
Unnamed went on a few missions before one day after returning from a mission she saw a child get hurt by adults and she tried to stop them, but another higher-ranking operative stopped her and told her that it was for the best, furious she resigned from her task and left the leaf village, not wanting to associate with monsters who would hurt a child and consider it okay
Unnamed lived alone for years, and in this AU, the team 7 (Kakashi, Naruto, Sasuke, and Sakura) visit her on one of their missions (right before Sasuke's initial turning evil) on accident.
She welcomed them into her home, as she recognized Kakashi and Naruto being the child who was being hurt, she treated Naruto kindly and lovingly and tried to spoil him, in hopes he'd want to stay, she'd scoff and tell Sakura and Sasuke to behave and get angry when they were rude to Naruto
Sadly, her actions pushed them all to leave, but she did give Naruto a carrier pigeon so if he ever wanted to talk, she'd be willing to listen (he would use this often)
Years later (in Boruto's time), she comes to the village seeking aid, as she had come to learn her clan was murdered (not an Uchiha a different clan who never chose a village to join but did let their people go off and choose for themselves) and wishes to try to repopulate so she was planning to use herself as a mere toy to bring back her clan as it was a rule amongst the clan "those who survive must thrive and bring about the next generation"
Of course, Naruto having gotten close with her via letters was upset and made sure to treat her well and not let her do as she desired by doing the whole thing,
Kakashi and her also rekindle their friendship and she rejoin the Leaf Village