The Spheres of Power (力の球, "Chikara no Kyū") were small, colored spheres that were the cores of the Shitōshin, the source of their existence and power. When their Spheres were removed and sealed by a priestess named Kanade on Hōraijima into a small comb box and hidden inside the Cauldron of Resonance, the Shitōshin were forced to remain on Hōraijima while sacrificing the island's half-demons into the Cauldron to sustain themselves. However, the comb box is removed from the Cauldron of Resonance with the spheres returned to their owners. Enduring after the Shitōshin were destroyed by Sesshōmaru, Sango and Inuyasha, Kyōra's power sphere, which, giving off a demonic aura in the shape of a phoenix, flew up into the sky, Jūra's sphere giving off a aura in the shape of a tiger, Ryūra's sphere giving off a aura in the shape of a dragon, except for the Gōra's sphere giving off a aura in the shape of a turtle, and the Spheres gathered and recreated the Shitōshin in their combined form. Once the combined Shitōshin was destroyed for good by Inuyasha's Adamant Backlash Wave, however, the Spheres were destroyed as well.
