The younger brother of Kodama Himegami's father Oousu no Mikoto and second prince of the Yamato court, he is the primary antagonist of the Summer Camp arc. He attacked Kodama's parents, leading to their deaths, before being defeated by her brother Yabiko. However, he maintains his existence by possessing people. He managed to possess Ouken Yamato when Ouken found a jar containing Kousu's soul.
After physically dying in the battle with Yabiko, his spirit fled and possessed a nearby human. He then spent that human's life ensuring the continuation of his bloodline by immersing himself with his concubines, and then sealed himself in a jar, planning to possess whichever of his descendants opened it. Since no one opened it and the jar could not be destroyed, it was buried for 2000 years, until it was rediscovered by Ouken Yamato.
Kousu has no consideration for fellow humans, seeing all others as trash below him. He regularly used to kill retainers in his father's palace, even in front of the emperor himself. This is likely due to his having such power that no one but his brother can stop him.
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