Dark One Piece theory suggests Saturn’s involvement in Bonney’s Sapphire Scale disease

With the One Piece manga wrapping up another heart-rending backstory, the fandom has come up with a grim theory that speculates the ominous origins of the Sapphire Scale disease.

The theory posits that Ginny contracted the Sapphire Scale disease in the One Piece universe through a cursed blue sapphire ring, potentially linked to the celestial body Saturn. 

The narrative suggests a sinister involvement of the Gorosei, each associated with different gems, infecting individuals perceived as threats to their plans. Ginny, intended for marriage to a Celestial Dragon, was cast aside after falling victim to the Sapphire Scale.

The theory finds its foundation in the real-world association of Blue Sapphire with Lord Saturn, who finds roots in Indian astrology as well. ("Shani"). It proposes that Saturn, represented by the Gorosei, curses blue sapphire rings given to slave wives of Celestial Dragons. Wearing these rings becomes a conduit for the curse, resulting in diseases such as the Sapphire Scale, as seen in Ginny's case.

Saturn's influence extends to controlling the marriages between Celestial Dragons and non-Celestial Dragons, with the aim of preventing the birth of "half-blood Celestial Dragon" children. The theory posits that Saturn's curse on the ring is so potent that it extends to the wearer's child, ensuring the disease is incurable and fatal.

Further complexity is added to the theory by suggesting that Saturn's devil fruit draws inspiration from the "Ushi-oni" - a Yokai capable of inflicting incurable diseases through curses. This dual association solidifies Saturn's role in the narrative, linking him to both the cursed rings and the diseases they cause.

The theory proposes that Saturn cursed Ginny's "Blue Sapphire ring" during her Celestial Dragon wedding, leading to her contraction of the Sapphire Scale disease. 

This curse, possibly intended to prevent the birth of a half-blooded child like Bonney, just adds to the layers of intrigue that Oda has been peeling back on the long-running manga for so many years.