Perhaps there could be a storyline where Naruto discovers he is an elf through some mysterious event. His journey then becomes about learning about his elf roots, like the history and culture of elves in this fictional setting. He might also have to face an evil force that is threatening both the elf and ninja worlds, and use his combined skills from both identities to save the day. Along the way, he could form alliances with other unique characters, some from the elf side and some from the ninja side, and develop new techniques that blend elf magic and ninja jutsu.
One possible storyline could be Naruto as an elf trying to fit into the ninja world while still having his elf heritage. He might face discrimination from some who don't understand his different nature.
One possible storyline could be Harry's struggle to accept his elven heritage. He might initially be confused or even ashamed, but then come to embrace it. Another could be that his elven side gives him unique magical abilities that help him in his battles against Voldemort. For example, he could have enhanced senses or a natural affinity for certain types of magic.
One possible storyline could be that Fenris is initially suspicious of the Elf Inquisitor due to their different backgrounds and the power the Inquisitor wields. Maybe they meet during a skirmish against a common enemy, like a group of darkspawn. Fenris sees the Inquisitor's combat skills and starts to respect them. As they interact more, they find they have common goals in terms of protecting the world from various threats.
Perhaps in a 'naruto and elf lemon fanfiction', the elf has a special power that the Naruto world needs to defeat a new and powerful enemy. Naruto and the elf team up, and during their adventures, they start to develop feelings for each other. Their relationship could progress from friendship to something more, with some tender and a few more suggestive scenes as they get closer, like a shared moment under a starry sky where their relationship takes a new turn.
A storyline could involve Naruto using his newfound Nara abilities to solve a mystery in the village. Maybe there's a strange phenomenon that's related to shadow - based jutsu, and Naruto, with his understanding of both Uzumaki and Nara powers, is the only one who can figure it out. He'd have to team up with other characters, and in the process, there would be a lot of character development and interesting interactions.
Another storyline might be that Millet is a secret organization in the Naruto world. Naruto discovers that this organization has been pulling the strings behind some of the conflicts. He has to infiltrate it and expose their true motives. This would be a great opportunity for Naruto to use his stealth and combat skills, as well as his ability to make friends and allies within the organization to bring it down from the inside.
One possible storyline could be that Naruto is chosen as a temporary Kazekage due to a threat that requires his unique skills. He then has to deal with internal conflicts within the Sand village while also facing external enemies. Another could be that there is some kind of prophecy that only Naruto can fulfill as Kazekage to save both Konoha and Suna.
In a Naruto and Derieri fanfiction, a possible storyline could be that Derieri is mistaken for an enemy in the Naruto universe. Naruto, being the one to see her potential for good, tries to convince others that she is not a threat. As they try to clear her name, they uncover a conspiracy that threatens both their worlds. This would involve a lot of mystery - solving and action as they race against time to stop the conspiracy.
One possible plotline could be that Naruto, in his travels, stumbles upon an elf realm. There, he meets an elf and they develop a romantic relationship with some 'lemon' elements like passionate encounters. Another could be that an elf is brought to the Naruto world and they have to navigate their cultural differences while falling in love in a more adult - themed way.
One possible storyline could be Ichigo being an outcast at first because of his strange powers. But as he shows his strength and determination, he gradually earns the respect of the ninja. Another could be that he's hunted by some dark ninja organization that wants to use his unique powers for their own evil purposes.
One possible storyline could be that Naruto's child in the fanfiction inherits some of his unique powers, like the Nine - Tails' chakra. And they have to learn to control it, with Naruto guiding them. Another could be that the child gets into trouble in the ninja world and Naruto has to use his influence and skills to protect them.