From what Chu Feng could do right now, he could easily kill those at the 4th level of the Origin realm. If he used the golden-coloured lightning, killing those at the 5th level of the Origin realm was like squashing an ant. Even people at the 6th level of the Origin realm might not be able to beat Chu Feng, not to mention the Spirit realm inner court disciples.
Chu Feng did not cripple them by destroying their hands or feet, but he crippled them by destroying their cultivation and he did all of that with one strike. Although he only pierced their dantians, when several hundred inner court disciples were laying on the ground, that wretched scene was not something that could be taken in by any normal people.