The Primordial Treasure Lingtian Space does seem a bit biased, as it has been a long time since a book appeared that could enhance the master's power.
Previously, treasures that appeared during the cultivation with the Green Ox and Eryao could possibly help them cultivate, enhance their culinary skills, or learn various skills from books.
However, some books couldn't be cultivated by them, but after transforming into humans, some books could be cultivated by them.
The Green Ox and Eryao, being constantly by the master's side, knew that there was only one book the master would not share with them.
That was an extremely heaven-defying and sinister book, and they knew even more that staying by the master's side would enable them to rapidly enhance their power, though the master did not allow them to cultivate it, not wanting them to take shortcuts in cultivation.
