Hayabusa was the first dog met by Amaterasu in her quest to defeat Orochi. He was found in Kamiki Village and could be fed to earn Praise. Hayabusa constantly accompanied his owner, Mushi. The pair would play games that often angered Mushi's Mama. Hayabusa is the guise name of Chu and was always referred to by his real name by the Eight Canine Warriors and Princess Fuse.
The original Hayabusa was killed fighting demons trying to save Mushi's father before Amaterasu began searching for the Eight Canine Warriors. The dog that was confused for Hayabusa was told by the dying original Hayabusa to save Mushi from an arrow at the Kamiki Festival. Mushi thought that he was the real Hayabusa because they were the same breed. After Amaterasu waited until night, Hayabusa explained this and the Loyalty Orb went to Amatarasu. Once the Kamiki Festival started, the arrow appeared and Hayabusa knocked Mushi out of the way just in time.
It is later revealed that Mushi knew that Hayabusa wasn't the real one all along, since he knew that his old dog would not have left his father to die.
In Ōkamiden, Hayabusa remained by Mushi's side in Kamiki Village.
In the beginning, Hayabusa was nothing but a normal dog. Later, Amaterasu would find out that he was indolent. It is revealed that that he isn't the real Hayabusa, but rather Canine Warrior Chu, as the real one had died, and because of the glaring resemblance, Chu took the place of Hayabusa. He stays in Kamiki after Amaterasu fights him, because before Hayabusa died, it told Chu that on the night of the Kamiki Festival, an arrow would kill Mushi. Before long, the night of the festival approached, and Orochi's sacrificial arrow materialized in the skies of Kamiki. As it flies, it was clearly aiming for Mushi before striking the house of the sacrificed maiden. Luckily, Chu was quick enough to rush Mushi out of the arrow's course before it impaled the child.
Hayabusa is a brown dog with darker markings. He is a Kai Ken, a Japanese breed. He wears a violet scarf, with the Loyalty Orb on it. As with all of the Canine Warriors, Hayabusa has the marking of the Satomi House on the back of his bandanna.
Hayabusa is not at all a difficult opponent. When the battle starts, Amaterasu can immediately approach him and begins her assault with farming techniques. After the farming procedures are completed, Amaterasu has to focus on attacking Hayabusa while simultaneously defending from the Canine Warrior's offense. When Hayabusa jumps into the air and perform a somersault before landing, his Loyalty Orb glowing, Amaterasu has to run to a certain distance, wait for Hayabusa to lunge at her, and when he has covered half the distance between his original position and Amaterasu's, execute a Sub-Reflector Counterattack to gain a Demon Fang and defend from the attack. Other attacks of the Canine Warrior includes a series of multiple lunge and bites, a hole-digging attack, and a land mine attack. When sufficient damage is dealt, Hayabusa will be stunned, a chance for Amaterasu to deal further damage.