Well, it could be about Naruto having some special powers or abilities he inherits from being the son of Seras. Maybe he has to deal with a world that doesn't understand his unique heritage.
In this fanfiction, it could be that Naruto is on a quest to learn more about his mother Seras. He might encounter people or creatures that knew her in the past. Along the way, he could face many trials and tribulations. His friends might be initially confused by his new revelations but eventually support him. And his journey could lead to a greater understanding of the ninja world's hidden secrets and his own place in it.
Well, it could be about Alucard and Seras teaming up to fight a powerful new vampire threat. Maybe they discover a group of vampires that are trying to take over the city and they use their combined powers to stop them.
One interesting storyline could be a crossover where Naruto's world of ninjas collides with Seras' vampiric world. Maybe Naruto is on a mission in a strange land and stumbles upon Seras. They could team up to fight a common enemy that threatens both their worlds.
Obviously Naruto would be one of the main characters. Since it's about him being the son of Seras, Seras herself would be an important character too, even if she might not be present in the story directly but her influence on Naruto would be significant.
In a 'naruto son of bellatrix fanfiction', perhaps Naruto has some of Bellatrix's wild and unpredictable nature. He could be on a journey to discover his true identity and how he came to be Bellatrix's son. This might lead him to explore the secrets of the wizarding world and his own ninja abilities in a new light.
Well, one possibility could be that Naruto inherits some of Gilgamesh's arrogance along with his power. Maybe he has a special ability to summon ancient Babylonian weapons. And he could use this in his battles in the Naruto world, like against the Akatsuki.
One possible plot could be that Naruto discovers his true heritage as the son of a princess from a hidden kingdom. He then has to deal with the politics and expectations of the royal family while still maintaining his ninja ways. Maybe he has to protect the kingdom from a new threat using his ninja skills.
In such a fanfiction, perhaps Naruto could be shunned by the village from the start. His 'devil' heritage might give him strange powers that he has to hide. He could struggle with self - identity, different from the Naruto in the original who is seen as a hero. Maybe he has to fight against the prejudice of the people who believe the devil's son can only bring destruction.
Well, it could be about Naruto having powers related to Hades on top of his ninja skills. Maybe he can control the dead or has some sort of underworld - like abilities that he uses in battles against the Akatsuki. He might also have to deal with the stigma of being the son of Hades in a world that doesn't understand such a thing.
Maybe Naruto is raised in Gotham instead of Konoha. He could inherit some of Catwoman's skills like stealth and agility, while still having his own ninja powers. He might fight crime in Gotham using a mix of his ninja techniques and Catwoman - like thievery skills, but for good causes.
Perhaps the story involves Naruto's journey to discover his true heritage as the son of Pegasus. He might face challenges from those who don't believe or accept his origin, and he has to prove himself. Along the way, he could make new friends or allies who help him in his quest.