It starts at a specific point in the manga, but I can't recall exactly without looking it up. You might want to check some manga forums or dedicated fan sites for the precise chapter.
It's both. In the academic and scientific communities, there's a real debate. Science is based on facts, evidence, and the scientific method, while fiction is imaginative. But in movies, it's often a concept to create exciting stories, like in sci - fi movies where scientific ideas are mixed with fictional elements.
One main point is the severity of Joan Crawford's behavior. Was she really as cruel as depicted? Another is the authenticity of specific incidents like the way she treated Christina during her upbringing.
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.
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.
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.