Ouken Yamato is the leader of the Kamigami, and a major antagonist through the storyline. He suffers from a case of apparent split personality; his original one is calm and composed but has been suppressed for ten years; the newer personality is a power-hungry maniac that is hellbent on releasing the seal on Amanohara to unlock its secrets. However, he is in reality possessed by the spirit of Kousu no Mikoto, the younger brother of Oousu no Mikoto, who possessed him when Ouken opened a jar containing Kousu's soul. He is generally referred to/addressed as Emperor Ouken.
Soul Collector - Ouken's maken is Soul Collector, which allows him to manipulate the souls of those around him. While primarily used to manipulate the memories of whoever he chooses, Soul Collector can also replenish Element by eating the souls of people.
Kotodama (Word Bullets) - Ouken can attack or defend using words, using his abnormal lung capacity and low frequency sound waves. Known attacks include:
- Gai (Barrier) - blasts everything backwards in a circle around Ouken.
- Ha (Break) - similar to a vocal cannon