Perhaps Harry Potter gets transported to Sesshomaru's realm. Harry, being lost in this new and dangerous place, catches Sesshomaru's attention. Sesshomaru, out of curiosity at first, decides to keep an eye on Harry. As time passes, he discovers Harry's unique magical abilities and his kind heart. Harry, on the other hand, is in awe of Sesshomaru's power and his otherworldly beauty. Their relationship could start from a simple acquaintance to a deep, meaningful bond as they face different trials and tribulations in Sesshomaru's world.
Harry would probably be cautious at first. He's used to dealing with humans and wizards, not demons like Sesshomaru. Sesshomaru, being a proud demon, might seem aloof. But Harry's intelligence and magical skills could pique Sesshomaru's interest. Harry might try to use his magic to understand Sesshomaru better, like using spells to translate Sesshomaru's language if there is a communication barrier.
Well, it could involve a world where magic from Harry's realm and the demon world of Sesshomaru collide. Maybe Harry gets transported to Sesshomaru's world and they initially have a lot of misunderstandings due to their different natures. But as time goes on, they start to see the good in each other and form a bond that goes beyond their different origins.
In a 'Harry Potter is Sesshomaru fanfiction', we might see a fusion of the two characters' traits. Harry could inherit Sesshomaru's pride and cold - bloodedness to some extent. The plot could involve Harry using Sesshomaru - like powers to fight the Dark Lord. For example, he could use a magically enhanced sword like Tenseiga. And there would be a mix of the Japanese yokai and the magical creatures from the Harry Potter world. It would be a unique blend of two very different mythologies and magic systems.
I'm not sure specifically as there could be many different interpretations in such a fanfiction. It might involve Harry Potter having a special connection with Death, perhaps being able to communicate with it or having some sort of mission related to Death. It could also mean that he has powers or knowledge that are associated with Death in a way that makes him a unique 'mate' in the context of the story.
A third plotline could center around the challenges they face as a couple. There could be opposition from both their respective worlds. In Harry's world, the wizarding community might not understand her relationship with a non - human from another realm. In Sesshomaru's world, demons might have their own opinions about a human - like Harry being his mate. This could lead to many conflicts and a journey of them trying to be together despite all the odds.
The main characters are Harry and Sesshomaru. But we can't forget about Dumbledore, who might play a role in Harry's journey to Sesshomaru's world. Maybe he has some knowledge about this strange connection and gives Harry advice before he goes. On Sesshomaru's side, his half - brother Inuyasha could also be involved. He might be suspicious or even hostile towards Harry at first, but then come to accept the relationship as he sees how it changes Sesshomaru for the better.
In such a fanfiction, the cultural differences between the Naruto and Harry Potter universes would be a big factor. Itachi, coming from a ninja - based society, would have different values and ways of life compared to Harry from the wizarding world. Their relationship as mates would bridge these gaps. Itachi's skills in combat and stealth could be used to help Harry in his battles against dark wizards. At the same time, Harry could introduce Itachi to the concept of friendship and loyalty in a different way than he has experienced in his own world. This fanfiction could explore how two very different characters from different fictional worlds can come together and form a strong bond.
One possible plot could be that Harry discovers a hidden connection between his wizarding world and the world of vampires. Dracula, for some reason, sees potential in Harry and decides to make him his'mate', which could mean an apprentice or a partner in some dark magic deeds. Harry, initially reluctant, gets drawn into Dracula's world as he realizes there are secrets about his own magic that Dracula can help him uncover.
A possible plot development is that the two worlds start to merge because of their connection. Harry Potter's presence as Sesshomaru's sister could be the catalyst for this. As the worlds merge, new species and magic could emerge. They would have to deal with the chaos that comes with it, like how different cultures and magic systems interact. There could also be a sub - plot about Harry Potter trying to find a way back to her own world while still fulfilling her role as Sesshomaru's sister in his world.
It would be really interesting. Maybe Riddick would introduce some of his tough - guy survival skills to the wizarding world. Harry could learn some new ways to face danger from him. And the two of them could go on adventures together, combining magic and Riddick's more physical combat abilities.