Ultraman Ace (ウルトラマンエース Urutoraman Ēsu?), also known as Ultraman A (ウルトラマンA Urutoraman A?), is the fifth of the Ultra Brothers to arrive on Earth. He was the first Ultra to possess two human hosts at the same time. He arrived on Earth to guard it from the evil alien mastermind Yapool. When Ace arrived on Earth, he merged with a man, Seiji Hokuto, and a woman, Yuko Minami, to alter his personality, giving Ace the courage of a man and a woman's love for peace.