Sora is likely a character created within the fanfic world. He could be a powerful shinobi with unique abilities that Naruto can learn from. Maybe he has a special chakra nature or some extraordinary combat skills.
Dazai is not based on a true story. Usually, characters like Dazai are formed through the author's imagination and artistic expression to create an engaging narrative for the readers.
Osamu Dazai's Collection was a collection of novels by the Japanese novelist Osamu Dazai. It included many works covering different styles such as novels, essays, and essays. The collection's theme was to describe the dark side of human nature. The style was humorous and satirical, and it was deeply loved by readers. Among them, the most famous works included "The World's Disqualification","The Setting Sun","The Wife of Wei Yong" and so on.