The Yin Soul was somewhat the primary step to attaining the perfection of the Dao Soul stage. The disparity was not something Xiao Ming could easily cross as the Mortal Soul and Dao Soul had a chasm that could only be overcame by going through the Six Trials and the Nine Tribulations. The Dao Soul after undergoing this would gain a tenacious defense towards normal soul attacks passively.
With the soul defense, not even a second or third Soul Severing Strike would be able to completely dissipate the Yin Soul, rather it might drain Xiao Ming's energy as the caster. But the stubborn Xiao Ming had his own means. He could not destroy the Yin Lord's soul in a strike, so he resolved to deal enough damage to turn the Death Lord's into that of an idiot.
INNATE DARK SOUL STRING!
