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.
Ja Whiting in Fantastic Fiction could potentially be an emerging author. In the realm of fantastic fiction, which encompasses various sub - genres like fantasy, science fiction, and horror, new names keep popping up. It could also be a character name created by an author for a unique story within this broad category.
I'm not sure specifically who 'Ja Johnstone' is in the context of 'Fantastic Fiction'. It could be an author, a character, or someone else related to the Fantastic Fiction world. More information would be needed to give a more definite answer.