Sister Lover was a Japanese manga about the love story between the protagonist and his half-sister. The ending of the manga had not been decided yet because the storyline had not yet ended. Some readers and the media speculated that the manga might usher in a happy ending where the protagonist and his half-sister could find their own happiness. However, these speculations were just speculations. The details of the ending of the manga would only be known after the work was completed.
One great yakuza fanfic is 'The Yakuza's Redemption'. It tells the story of a yakuza member who tries to break free from the criminal underworld. Another one could be 'Yakuza Love', which focuses on the relationships within the yakuza families. And 'Yakuza Legacy' is also quite interesting as it delves into the family traditions and power struggles in the yakuza world.