Hayate is the lover of Hokuto. When Hokuto expresses concern over the fate of her missing brother Kairi, Hayate vows to assist her in looking for him. Hokuto decides to enter the first EX tournament in hopes that the tournament might also attract her brother and she can find him and bring him home. Hayate does not enter the tournament, believing that it is beneath him, but he stays close by Hokuto's side.
While Hokuto is in the middle of a fight, Hayate believes that he sees Kairi in the middle of the crowd. Acting swiftly, he advances to Kairi's location. Much to his surprise, Kairi vanishes. Trying desperately to pick up Kairi's trail, he spots Kairi off in the distance. He runs to him, but is knocked out by an attack from behind by a man in a black gi.
When Hayate regains consciousness, Kairi is gone. He returns to Hokuto, ashamed to tell her the news that he lost Kairi. Hokuto forgives him. When the second EX tournament begins, Hayate decides to enter in order to better aid Hokuto's search. As a result, they are forced to split up for a while. Hayate does rather well against the competitors, and manages to accomplish something he had planned for. If it ever turned out that Hayate and Hokuto were pitted against one another, Hokuto would throw the fight, and Hayate would be allowed to advance.
His bout with Hokuto begins, but Hayate notices something odd about Hokuto's behavior. Her strikes are real, and Hokuto is not pulling any of her attacks. He is unaware of the transformation that has taken place within Hokuto. Surprised and taken off guard, he realizes that she has no idea who he is, and is fighting to the death. Trying desperately to defend himself from her attacks without harming her, Hokuto launches a series of attacks that are uncharacteristic of her normal fighting style. Unable to defend himself, he is mortally wounded.
The sight of a dying Hayate awakens something in Hokuto's sleeping mind. She becomes herself again as she begins to realize what she has done. Hayate pledges his undying love to Hokuto as he takes his last breath in Hokuto's arms.