With the gemstone in hand, Fang Jie looked at it, then directly integrated it into a Skeleton Conversion Field.
This is a troop building upgrade gemstone, not a blueprint. Therefore, it can only upgrade one building, which is solely a Skeleton Conversion Field, not allowing all Skeleton Conversion Fields to be upgraded.
This was somewhat frustrating for Fang Jie.
"Well, as long as there is one, research can be conducted, and a blueprint will eventually be developed."
After all, it's a Miracle Building, and although research isn't easy, his territory indeed has the capability for researching. Once there is a physical object, as long as sufficient resources are invested, it will eventually be discovered.
It just requires some time, possibly measured in years.
The most important thing now is to upgrade the building first.
