Seperate and One
The three Incorporeal Souls...
The Original Spirit, the root of Intelligence, was where Mental Realm Talent lay, what gave cultivators their sharpness and insight, their senses...
The Yin Spirit. It was the source of life, what fueled you, what kept you alive and powered the other Incorporeal Souls and your entire body for that matter.
The Yang Spirit… it was one's self-awareness and identity; it should have been the Ego.
When Ryu was born, he lost two of these souls. Or more accurately, he lost one, and the second was heavily damaged after being taken and scavenged.
His Original Spirit was his Perfect Blackbody, a soul that he didn't have by his side for the longest time. Only a small part of it was left remaining, which was why he usually thought that he had two of his Incorporeal Souls, when it was really more like 1.5.
His Yang Spirit… this was his Dao Heart, his Spiritual Foundation, the very existence that had just taken over his body.