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.
Yes, you can. Since you can use public domain stories freely, you can create products or services based on them and then sell them. For example, you could write a novel based on a public domain story and sell it. Just make sure you follow all the legal requirements and ethical norms while doing so.
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.
Firstly, set your writing goal as promoting positive values. Then, use more general and positive descriptive words. For example, if you want to describe a character's physical state, you can use words like 'gentle movement' instead of something sexualized. And always be aware of the ethical boundaries in writing.