In this fanfic, it could start with Naruto getting into some serious trouble during a mission. Kakashi, feeling an unexplainable urge to protect him more than usual, starts to investigate. He discovers a long - lost memory or a secret message that reveals Naruto is his son. After that, Kakashi has to face the fact that he has missed out on so much of Naruto's life. He then makes it his mission to be the best father he can be, training Naruto not just in ninjutsu but also in life skills and values, and they develop a strong bond based on mutual understanding and love.
One possible plot could be that Kakashi discovers Naruto is his son in a surprising turn of events. Maybe there was some hidden truth about Naruto's birth that was concealed all this time. Kakashi then has to deal with the newfound father - son relationship while also guiding Naruto in his ninja training. He could be more protective and pass on some of his unique skills more intimately.
The plot could revolve around a time -travel scenario. Naruto somehow gets sent back in time and meets Kakashi's father. Together, they could work on changing some of the events that led to the darker times in the village's history. For example, they might try to prevent certain tragedies that affected Kakashi's family.
The plot could involve Kakashi adopting Naruto. Kakashi would then be responsible for Naruto's upbringing, teaching him not only ninja skills but also life lessons. For example, he could teach Naruto how to cook simple meals, which is a basic life skill. This would show the domestic side of their father - son relationship.
A plot might be that Naruto is born in the Naruto universe but has dreams and visions of Sparda. As he grows, he starts to show extraordinary powers that are not normal for a ninja. He then embarks on a journey to find out who Sparda is and discovers that he is his father. Along the way, he meets characters from the Devil May Cry universe who help him understand his powers. He has to fight against ninja clans who want to use his powers for their own gain and demons who want to corrupt him. He uses his Naruto - like tenacity and Sparda - inspired powers to overcome all these obstacles.
A plot could revolve around their son being born with a rare illness that Sakura, despite her great medical skills, is unable to fully cure. This leads to a search for a cure across different lands. Naruto, being the Hokage, has to balance his duties with helping his son. Their son, in the meantime, shows great courage and determination, not wanting to be a burden. He trains hard to become strong enough to face whatever comes his way, and along the journey, they encounter many challenges and make new friends who join them in their quest for a cure.
One possible plot could be that Naruto is wrongly accused of a serious crime in the village and is banished as a result. Feeling betrayed, he decides to confront Kakashi, who he may see as representing the village's unjust decision. The fight could be a way for Naruto to vent his anger and also prove his innocence.
The plot could be that Naruto gets a special mission to protect Kakashi's face from a group of rogue ninjas who want to steal Kakashi's identity. Naruto has to use his unique skills to fend off the attackers and keep Kakashi's face safe.
Well, the plot could revolve around Kakashi providing Naruto with a more stable family - like environment. He might cook for Naruto, help him with his studies at the ninja academy in a more hands - on way, and also be there to support Naruto emotionally when he has nightmares about being alone. This could lead to Naruto growing up more confident and perhaps even developing new skills faster as he has someone constantly guiding him.
One possibility could be a misunderstanding. Maybe Kakashi is framed for something that makes Naruto believe he has betrayed him. For example, an enemy could use a clone of Kakashi to perform a heinous act, and Naruto witnesses it without seeing the full picture.
Well, it could be that in this fanfic, Kakashi discovers a new potential in Naruto. He might train Naruto in some ancient and forgotten ninja arts. This would set Naruto apart from his canon self. Also, their relationship could be explored more deeply, like Kakashi becoming a father - figure to Naruto, and this emotional bond could influence Naruto's growth as a ninja.
A possible plot could be that in a mission gone wrong, Naruto and Kakashi get separated from the rest of the team. They end up in a strange place where they have to rely on each other more than ever. As they face various challenges together, their bond deepens and Naruto realizes his feelings for Kakashi, leading to a kiss.