I recommend the book "Possibly a Fake Silver Soul". It tells the story of Jiang Cheng, a transmigrator, who met the owner of Xinghai District and his girlfriend, Jiang Hua, who were traveling in the universe in the dragon vein of a certain planet. Later, he came to Earth and met his teacher, Yoshida Shoyo, who had influenced his life. He also met a group of friends. This included the transmigrator Okita Soki. This is a Silver Soul Doujinshi novel, don't miss it. I hope you like this fairy's recommendation. Muah ~😗
I'm not entirely sure as I haven't read it in detail. But generally, it might be about some unique characters and their adventures, perhaps with elements of mystery or fantasy given the rather intriguing title.
Gintama is purely fictional. It's filled with imaginative characters and scenarios that are not rooted in real-life events. The creators crafted a unique and entertaining fictional world for the audience.