A good plot might be that the male reader is an outcast in the village because of some special power he has. Kakashi is the only one who doesn't fear him and decides to understand him better. As they spend time together, they find that they have a lot in common and start to fall for each other. Or perhaps they meet during a time - travel incident where they have to fix something in the past. This adventure brings them closer and they realize their love for each other.
One plot idea could be the student reader struggling with a difficult jutsu, and Kakashi takes them aside for special training. During this time, a deep bond forms between them as he helps them overcome their self - doubt. Another idea is that the reader is on a dangerous mission and Kakashi, as their teacher, has to make a tough choice to protect them, which reveals his hidden feelings.
Maybe the reader has a special ability that Kakashi needs to understand in order to solve a mystery in the village. So, they team up and during their investigation, they start to understand each other better. Their relationship develops from a professional one to a more personal and friendly one as they share their pasts and hopes for the future. This plot allows for a lot of character exploration and interaction without any adult content.
One idea could be that the male reader is a dragon in human form from another dimension. He comes to the HTTYD world to seek help because his own dimension is in danger. The Vikings initially suspect him but as they learn more about his situation, they team up with him. Another plot could be that the male reader's dimension is slowly being consumed by the dark forces of the HTTYD world's past. He has to work with Hiccup and Toothless to find a way to stop it before his dimension and the HTTYD world are both destroyed.
A good plot could be that the male reader is a normal guy who gets caught in the middle of a fight between Spider Gwen and a powerful villain. Spider Gwen saves his life, and he becomes determined to help her in any way he can. He starts training to be her sidekick of sorts, and during this process, they develop feelings for one another.
A possible plot is that Naruto discovers a hidden power within Kakashi that even Kakashi was unaware of. This discovery leads them on a journey to explore the origin of this power. Maybe it's related to an ancient clan. As they dig deeper, their relationship grows stronger and they face many challenges together from enemies who also want this power.
One idea could be that the male reader is a new member of the Straw Hat crew. He and Robin gradually develop a bond during their adventures. For example, they could be exploring an ancient island together and the male reader saves Robin from a hidden trap. This shared danger could be the start of their relationship. Another plot could involve the male reader having a special power or knowledge that Robin is interested in, and through their interactions, they fall in love.
Maybe the male reader is a survivor in a post - apocalyptic world that has been influenced by the same dark forces that created Female Pyramid Head. They cross paths, and at first, she is hostile. However, the male reader has a special ability to see the 'good' in her. He offers her kindness, which she has never experienced before. This kindness gradually thaws her cold exterior, and they develop a relationship that defies the harshness of their world.
One idea could be a story where the reader is a new hero in the Injustice 2 universe. Superman, initially suspicious, starts to see the good in the reader. As they team up against common threats, a bond forms between them. Maybe the reader has a unique power that Superman comes to rely on.
One idea could be that the reader is a new student at the university where Tadashi studies. They meet in the robotics lab and start collaborating on a project, which leads to a budding friendship and then romance.
A really interesting plot could involve the reader being a Muggle - born who discovers a magical ability that no one has ever seen before. The Weasley twins, being curious and always interested in the extraordinary, take the reader under their wing. They explore this new ability together, getting into all sorts of adventures and misadventures at Hogwarts. This could also lead to a romantic relationship as they get closer through their shared exploration.