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.
Well, in a 'naruto is the son of sparda fanfic', the plot could start with Naruto's birth. Maybe his mother was from the Naruto world and his father was Sparda. Naruto grows up an outcast in his village because of his strange powers. He is then guided by a mysterious figure who reveals his true parentage. From there, he travels to different dimensions to learn about his father's legacy and gain the power to protect his world from a looming threat that is attracted to his unique heritage. As he does this, he also tries to gain acceptance in his own village.
Well, one possibility could be that Naruto inherits Sparda's incredible demonic powers. He might use these new powers to protect Konoha in ways he couldn't before. For example, his combat skills could be enhanced to a whole new level, allowing him to defeat enemies with ease. Also, his relationship with his friends might change as they try to understand this new side of him.
The main antagonists could be the Akatsuki from the Naruto world. They might see Naruto's new powers as a result of being Sparda's son as a great asset and try to capture him to use for their own evil plans, like creating some sort of super - weapon or using his power to take over the ninja world.
Well, it could involve Harry having some of Dante's devil - slaying abilities. Maybe he uses them to fight the dark forces in the wizarding world that Voldemort represents in a more unique way than just magic. For example, he could have enhanced speed and strength like Dante to take on Death Eaters.
Yes, there might be some out there. There are a lot of fanfic writers who come up with really creative crossovers. You can start by looking on popular fanfic websites like Archive of Our Own or FanFiction.net. Some writers might take the idea of Naruto being the son of Sparda and build an amazing story around it, exploring how Naruto's ninja skills could be combined with Sparda's demon - slaying abilities.
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 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.
It's also unique in terms of character interactions. Naruto's values from his ninja world clash and blend with the values of the DxD characters. For example, his sense of loyalty and friendship is put to the test in a world where power struggles between different factions are common. And his Sparda - like powers make him a target and a potential ally to many in the DxD world.
The fanfiction might explore the concept of a Naruto character being a descendant of Sparda in many ways. For instance, the character could have a special form or transformation similar to Dante's devil trigger in the Devil May Cry series (since Sparda is from that). This form could give them enhanced strength, speed, and abilities. They could also face challenges related to their dual heritage, like being shunned by some in the Naruto world who fear the unknown powers. And the story could revolve around how they overcome these prejudices and prove themselves as a valuable asset to their comrades and the entire ninja community.
One great 'Naruto son of Sparda DxD' fanfic is 'Naruto in the DxD World'. It combines the unique abilities of Naruto, as if he were the son of Sparda, with the exciting and complex world of DxD. The story has some really cool fight scenes where Naruto uses his ninja skills along with his new 'Sparda - like' powers.