Maybe a Harry Potter character gets sent to the Naruto universe. They are faced with the harsh reality of the ninja world where they have to let die their peaceful and magic - reliant mindset in order to survive. For example, they might have to accept that in the ninja world, not all problems can be solved with a simple spell, and they have to adapt to more physical and strategic combat, which means letting go of their old ways.
One possible plot could be that a Naruto character is transported to the Harry Potter world and has to let go of their chakra - based powers as they don't work there and learn magic instead, but they struggle with 'letting it die' i.e. their old way of fighting.
One plot could be that Harry Potter is bitten by a vampire during one of his adventures outside Hogwarts. He then has to struggle with his new vampiric nature while still trying to protect the wizarding world from dark forces. Another idea is that there is a hidden vampire community within the wizarding world that Harry discovers, and he has to deal with the politics and secrets there.
One possible plot could be that Sesshomaru somehow ends up in the wizarding world of Harry Potter. Maybe a magical portal or a powerful spell goes wrong. He then has to navigate this new world with its own set of rules and magic, and he might encounter Harry and his friends.
Well, it's a bit difficult to directly recommend a particular 'Let it die a Naruto and Harry Potter fanfic' without more information. However, when you search on fanfic platforms, pay attention to the summaries. If it mentions an interesting crossover concept between the Naruto and Harry Potter universes in relation to the 'let it die' theme, it might be worth checking out. For example, it could be about a character from one universe facing a situation where they have to let something die in the other universe's context.
One possible plot idea could be how Snape deals with the physical and emotional changes during the pregnancy while still trying to maintain his role at Hogwarts. Another could be the reactions of other characters like Harry, Hermione, and Ron when they find out.
Well, for a Harry Potter and Naruto crossover fanfic, a cool plot could be that there is a dark force emerging that is a combination of Voldemort's magic and the Akatsuki's evil intentions. Harry Potter and Naruto then join forces. They start by training together, with Naruto teaching Harry some basic ninja moves like tree - walking to improve his physical abilities, and Harry teaching Naruto some basic spells for protection. Along the way, they gather their friends from both worlds, Hermione and Sasuke for example, to fight against this new threat.
One possible plotline could be Naruto trying to find a way to visit the Harry Potter world. He might search for some kind of magical portal or a powerful spell that can transport him there. Another plotline could be Naruto using the ideas from Harry Potter books to improve his ninja techniques. For example, he could learn about the concept of wandless magic and try to apply it to his chakra control.
One plot idea could be that there is a strange magical - scientific anomaly that threatens both the wizarding world and the Watchmen's world. Harry and Jon have to team up to figure out what's going on and stop it. Maybe it involves a dark wizard using some sort of Watchmen - inspired technology to create chaos.
One possible plot could be that in a dark and alternate universe. Naruto might be facing an overwhelmingly powerful enemy that he simply can't defeat. Maybe an ancient evil has been unleashed and Naruto sacrifices himself to save the village. This would be a very tragic take on the Naruto story as he is usually seen as a symbol of hope and victory.
One idea could be exploring what would happen if Harry had a twin sister who was sorted into Slytherin. It would add a whole new dynamic to the story, with her having different views and friends than Harry. She could be caught between loyalty to her house and loyalty to her brother.
A plot could be that Voldemort somehow gets access to the power of the tailed beasts from Naruto's world. Harry Potter and his friends have to travel to the ninja world to team up with Naruto to stop Voldemort. The Day of the Dead could be when Voldemort plans to use the power to resurrect his most powerful followers. Another idea is that a curse from the wizarding world starts affecting the ninja world, and during the Day of the Dead, Naruto discovers that the only way to break it is to use a combination of wizard magic and ninja chakra. They then seek the help of Harry Potter.