Genbu is an auspice, a once ordinary animal that attained sentience and godlike powers. Along with his fellow auspices Byakko, Suzaku, and Seiryu, collectively known as the Four Lords, he became the companion of the hero Tenzen. After many adventures, Tenzen was killed battling the powerful rogue Auspice Koryu, though the Four Lords were able to place a seal on the menace. Genbu then kept watch over the sealed beast beneath Hells' Lid for the following centuries.
When the seal on Koryu begins to fail, Genbu decides to seek out the aid of the Warrior of Light, by luring them to Hell's Lid. When the Warrior reaches his location, Genbu engages them in battle as a test and, upon defeat, explains his history. Genbu subsequently recruits the Warrior of Light, Tataru Taru, and Soroban to his mission. He tasks the Warrior in challenging and defeating Byakko, Suzaku, and Seiryu in battle in order to purge them of the aramitama that has begun to corrupt them. Meanwhile, with Tataru's help, he begins to train Soroban to be able to maintain Koryu's seal.
After the Four Lords are reassembled, they attempt to strengthen the seal on Koryu, only to have the creature free itself and slay Genbu. However, Soroban allows Genbu's spirit to inhabit his body. Together with the Warrior of Light and Tenzen's spirit, the Four Lords successfully reseal Koryu.
Genbu, still co-inhabiting Soroban's body, explains that his spirit will eventually pass on. However, this may take up to 500 years, which will give him plenty of time to train Soroban to be his successor. He thanks the Warrior of Light and Tataru for their assistance, and rewards them with a large amount of treasure to refill the Scions' coffers.
Black Tortoise or Black Turtle is one of the Four Symbols of the Chinese constellations. Despite its English name, it is usually depicted as a turtle entwined together with a snake. According to Wu Xing, the Taoist five-elemental system, it represents the water-element, the direction north, and the winter season. Thus it is sometimes called the Black Tortoise of the North. It is known as Xuan Wu in Chinese, Hyeonmu in Korean, Genbu in Japanese, and Huyền Vũ in Vietnamese.The