The Yang serves as a countermeasure to combat the the life-draining power of Akujiki, the evil soul-eating sword. The more the Yang coolected, the more power enough for it to save the life of whoever possesses Akujiki.
Hotsuma, now the leader of the Oboro Clan, was forced to kill his brother Moritsune in the cruel Suppression Ritual between the sons of the Oboro clan's Main Household, but Moritsune willingly sacrificed his Yang to protect Hotsuma. But due to the Golden Palace Incident, the seal had broken, and Akujiki's gluttony for souls had awakened. Hotsuma was forced to wield Akujiki and satisfy its vile hunger, but he is protected by the yang which is also that of his own soul. He uses the blade to destroy the Hellspawn and soon Hiruko who uses the yin of his victims and his puppets to gain power.
The Yang is the opposite of the Yin.
- In Japanese spirituality Yang is called Kon, the actual soul that gives life.
- In the Oboro ritual, Akujiki would be forced to feed upon the Yang energy of the defeated Oboro heirs instead of Yin, which would weaken the demonic parasite Akujiki is made from, and put the demonic katana back into stasis to be controlled.