Ultraman Ace (1972–1973)

Ultraman Ace takes the genre in a different direction. At the beginning of the series, it takes a man and a woman to change into him, giving Ace the courage of a man and a woman's love for peace. Yapool, an ancient interdimensional creature from ancient times with similarities to Satan and Legion, sought after the planet of Earth and tried to conquer it with a campaign that involved his experiments known as Choju. The first super weapon sent to Earth, Velokron, ravaged a city and took on TAC, a special forces unit created by the Self Defense Force to defend the Earth from kaiju. Two of Velokron's unfortunate victims were Hokuto Seiji and Minami Yoko.
Before they were dead long the first five Ultra Brothers, Ultraman, Zoffy, Ultraseven, Ultraman Jack, and Ultraman Ace, decided to revive the duo for trying to help young children get away from the Choju and to fight off Yapool's forces. Ace decided to be the one to go as he had both of them be his host. Yapool has used not only Chojuh, but also recruited other aliens, humans that sold their souls to him for Choju possession, and even himself to assassinate Ace and TAC only to be brought down in absolute defeat. After the destruction of one of Yapool's oldest Choju, Lunatyx, Minami revealed she was one of the last natives from the moon and gave her Ultra-Ring to Hokuto as she had to leave, but she would return every once in a long while. Ever since Hokuto has been Ace's host and their efforts were just the same. Yapool became desperate by combining the bodies of a selected few to create Jumbo King only for him to fail and have Ace fly off to his home world of M-78. Ever since Ace has showed up to help later Ultras in their times of need. Ultraman Ace still retains his connection to Hokuto Seiji as his human host, as seen in Ultraman Mebius series and movies.  - From Wikipedia-