The World Tree Heart Fragment was a Demigod grade treasure after all, one at the top among treasures of its category, in fact.
Before this, Bai Zemin thought that the World Tree Heart fragment was below the Collector's Pocket Watch.
After all, even if the World Tree Heart fragment granted more stats and even doubled the Health points obtained from the moment the holder managed to build a connection with it, it was still inferior to having a world with a 10:1 time ratio compared to the outside.
However, he soon realized that he underestimated the power and capability of the World Tree Heart fragment now that he saw what Wu Yijun was capable of.