Simply put, with his current 'Little Five Elements Yin Yang Dao Embryo,' he can directly manipulate the Five Elements Energy between Heaven and Earth. These energies are essentially Five Elements Particles, signifying that with Zheng Yi's current constitution, his affinity for Five Elements Energy has reached an astonishing degree.
This is akin to the magnificence of Spirit Root strength.
If a Top-Grade Spirit Root is like a powerful transmitter and receiver, capable of clearly picking up the signals of Spiritual Particles between Heaven and Earth, then converting these signals to enhance one's control over the particle flow.
Then Zheng Yi's Little Five Elements Yin Yang Dao Embryo expands the contact surface and sensitivity to particles, also maximizing the efficiency of utilizing Heaven and Earth Spiritual Particles.
Though not as high as the legendary Earth Spirit Root or Celestial Spirit Root, it still rivals the qualifications of a Top-Grade Spirit Root.
