Kon

is the heart or soul that all living beings possess like hanyō. It works in conjunction with haku that allows a body to move. Unlike Haku, Kon, does not reside in the body and does not have its own physicality. When kon and haku are unified, it is called kokoro. Kon and haku are interactive and independent. When the body dies, the kon returns to or ether. When Hakudōshi was creating various demon puppets using haku to animate them, the kon spirits of the demons were released after their initial deaths.

Since Sesshōmaru has been hit from Kirinmaru's Demon Fireball, it causes to drain his of very lifeblood essence (haku), Towa use the Zanseiken to absorb the demonic energy to absorb the Kirinmaru haku to save her father, only to end up her soul being suck and her kon have been drained leaving unconsciousness until Akuru come and revive her with his pinwheel.

According to Kirinmaru since his daughter Rion can't move anymore, her kon may have sealed within these bones and grave soil but as time passes, she will expand the haku required to move that vessel.