Byakko's Great Underwater Decisive Battle. Momo, Rina, and Ryuuji come with Riku and Nazuna to a water field in the Fukumaden. Riku, Kogenta, Nazuna, and Horin then must fight underwater against the Chi-ryuu's Mutsuki (Shikigami - Gyoujaku no Ebihiko) and Daikan (Shikigami - Shuusui no Ryuukon).