The Sapphire Scale disease was created by the World Government against the Ancient Kingdom
Sapphire Scales is an extremely rare and seemingly incurable disease which causes sapphire-like stones to grow on the victim’s skin. The sapphire-like stones can accelerate from exposure to natural light, whether sunlight or moonlight. Although the growth of the stones can be stalled by avoiding light, these stones will eventually cover the victim’s entire body, leading to their death within a few years.
It is currently unknown how the disease is contracted, Ginny somehow contracted the disease during her slavery in Mary Geoise. It seems to be hereditary, considering Bonney developed it after her mother. The cure for it, if there is any, is also unknown.
The disease is extremely rare and it is stated to be even rarer than Amber Lead Syndrome, which the majority of doctors throughout the world are completely unaware of it, saving only a very few.
When Bonney was five years old, Dragon finally managed to find a doctor who has the knowledge of the disease to give a correct diagnose to Bonney. He estimated that she had five years maximum left to live. However, Bonney has currently exceeded this estimate by two years and no longer shows any symptoms of the disease.
I believe Chapter 1098 may have given us the way (or at least a way) that the World Government used to get rid of the people from the Ancient Kingdom. We now know of the Sapphire illness, how it is incurable and causes death, but we also know that the symptoms are “accelerated” when exposed to natural light, or just “Sunlight”. What if, that disease was created 800 years ago as a way to indirectly kill the civilians, “exposed” to the Sun God Nika ?
You know, like, “you worship your god, you die a horrible way”.
Now I know Nika (Luffy) doesn’t emit sunlight by himself , but it can also just be a metaphor for the “exposure to freedom”: “you want to be free, you die”
Because obviously, being forbidden to enjoy sunlight isn’t the best freedom there is.