Ultraman Taro: Certain Kill! Taro's One Blow of Rage!

Kotaro Higashi trained to be a boxer, but after an icident with Astromons, he was killed. However, his body was brought to Nebula M-78 where Mother of Ultra saved his life by joining him with Ultraman Taro. Taro had spent many years training, honing his skills based on those of the other Ultra Brothers to become strong. The two returned to earth as a new kaiju era was beginning.