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.
There are also fans who might be a bit nervous. They worry that the fanfiction they wrote might not be up to the standards that Dan and Phil expect. But overall, most fans are positive about it. They see it as a unique interaction between their idols and the fan - created content world. And this can lead to more fans being motivated to write better and more creative fanfiction in the hope that it might also be read by Dan and Phil.
The reactions would be complex. Kim's best friends would be in disbelief at first. They might question how this could happen so suddenly. Kim's parents would likely have a serious talk with her about the consequences and the future. Ron's friends might tease him a bit but also realize the seriousness of the situation. Ron's family, especially his mother, would probably start making plans to help them out. As time goes by, all of them would gradually accept the situation and offer their love and support to the young couple.
Well, Serena would probably be over the moon. She's always been close to both Dan and Blair and would see this as a wonderful union. She'd be there for Blair during the pregnancy, helping her with shopping for baby clothes and giving her advice. Nate, on the other hand, would be more practical. He'd offer to help Dan with any financial or housing arrangements they need to make for the baby. And then there are the more catty friends, like Penelope and Hazel, who might be jealous and make snide remarks about how Dan and Blair got pregnant so quickly, but deep down they're just envious of their relationship.
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.