Although he despised Sage Kumu's methods, Chen Jingzhai did not underestimate him. After all, he was a Golden Core Sage. His methods had to be copious and vicious.
However, with two Grade 4 experts by his side, Chen Jingzhai was not afraid. He had made up his mind to attack Sage Kumu. With that plan in mind, he immediately escaped from the East Pole Spirit Turtle Island with Hei Wuchang and Hei Ji.
Speed was important in battle, so he decided that it was best to just take out Sage Kumu's hometown before he noticed that something was amiss.
This time, Chen Jingzhai did not lose his mind. This was called striking while the iron was hot.
If this happened at a time before Hei Ji appeared, even if he had magic treasures and the Primordial Essence Grotto-heavens, he would not have been so reckless. However, with Hei Ji and Hei Wuchang around, Chen Jingzhai was not afraid as long as he was not facing a Nascent Zhenjun.