The description of Han Tianhe and Liu Yanshan in their profiles stated that they only had one main fey each.
Besides their main fey, which was Creation Breed, the other feys were all Myth Breed.
This was the usual path that experts took as it already took a large number of resources to nurture a Creation Breed fey.
It would take multiple times the number of resources to evolve a Creation Breed fey.
Although Han Tianhe and Liu Yanshan had Connected Beast Park's support, Connected Beast Park did not have enough resources for them to evolve their other feys to Creation Breed.
Resources were limited, and evolving their other feys to Creation Breed would divert resources away from Han Tianhe and Liu Yanshan's current main fey.
Lin Yuan was a little disappointed that Han Tianhe and Liu Yanshan only had one main fey each.
This meant that even if the Invisible Demon killed them, he would only be able to gain two World Crystals.