Choso is not dead in the manga. The plot hasn't taken that turn. Usually, character deaths are significant events and for Choso, that hasn't happened yet.
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.
A 'choso fanfic' is likely a fan - made fictional work centered around a character named Choso. It could involve various storylines like adventures, relationships, or self - discovery that the author imagines for this character.
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.