Although Tang Zhen was burning with anger, he didn't directly kill the blue-faced cultivator. Otherwise, it was very likely that the enemy would take extreme actions.
A little impatience would spoil a great plan, and he was naturally aware of this.
Since Arel was still in their hands, Tang Zhen could only spare his dog life for the time being. After saving the mother and son, he would definitely make the blue-faced cultivator pay a painful price.
Family was Tang Zhen's reverse scale. This group of people actually used this to threaten him and had already been viewed as a life and death enemy by Tang Zhen!
The words of the blue-faced cultivator had already proved that this matter was related to the continent-level city in the war zone of the spirit ruins. If Tang Zhen wanted to save Arel, it was inevitable that he would have to fight with the continent-level city.