Sukuna does die in the manga. The way it happens is quite dramatic and ties in with many other elements of the story, adding depth and tension to the overall narrative.
One possible story could be that Mimiko is bitten by a mysterious vampire one night while walking alone. She then starts to experience strange cravings and enhanced senses. At first, she's terrified, but as time goes on, she begins to embrace her new vampiric nature.
The wizarding community would be shocked. Guns are not part of their world, and for Harry to use one to kill Voldemort would be unthinkable for many. There would be outrage from some traditional wizards who believe in magic as the only proper way to fight.
Most of the fandom would probably be horrified. Naruto is known for his positive values, and killing a family member is completely against that. There would likely be a lot of criticism towards the author of such a fanfic.
Yes, there might be. There are many fanfic communities out there where such stories could exist. You could try searching on popular fanfic websites like Archive of Our Own or FanFiction.net.
No. Ryomen Sukuna is a fictional character from Japanese mythology and modern manga/anime. He doesn't have a basis in a true historical event or person.
A 'adachi x nanako fanfic' could potentially explore the relationship between Adachi and Nanako. It might focus on their interactions, how they support each other, and the development of their friendship or a possible romantic connection. Maybe it shows how they grow together through shared experiences in their fictional world.
Nope. Ryomen Sukuna has no basis in reality. It's a product of the creative minds of the writers and illustrators who designed a captivating fictional character for the enjoyment of the audience.