There were no records of secret skills or Dharmic arts of the Dragon race that were meant for killing within the Yin Spirit section.
Among them, there was a spirit refinement technique from the Dragon King Desolate Ocean and it described how one should consume the essence of day and night to strengthen their bodies and bloodline!
Under normal circumstances, Su Zimo would encounter great difficulties in cultivating the Yin Spirit section.
Previously, if Die Yue had not guided him by the side, there was no way he could have comprehended the Bones Strengthening, Tendons Transformation and Body Tempering sections within a few short years.
Before she left, she also mentioned that it would be difficult for Su Zimo to continue with his cultivation post her departure.
That was the truth as well.
Later on, for the Organs Refinement section, Su Zimo met with a great bottleneck and was stuck for a long time.