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.
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.
Definitely! The Hajime no Ippo manga has a compelling plot with lots of exciting boxing matches and emotional character arcs. The way it portrays the sport and the growth of the main character makes it really enjoyable.