Too Weak

At Foundation Establishment realm cultivators can use Qi outside there bodies that means they can learn secret skills which uses elements to attack each other.

Jiang Hao hadn't learned those skills but he had no doubt that other Foundation Establishment realm cultivators have definitely learned them as they were in Foundation Establishment realm long enough to do so.

Cultivators can master secret skills of any element irrespective of their spiritual roots but their strongest and most efficient attacks will definitely related to the element which is attuned with their spiritual roots.

Jaing Hao doesn't want to beat them one by one, although it would have been enough to assert his dominance but the impact won't be high enough, so he had other plans. He also wanted to test his limits.

Although he didn't learn any secret skill he can still use his spiritual qi to attack.