young Taro wanted to join the Ultra Brothers but his parents thought that he was still too young and inexperienced. As a result, he started training with his father, though he also went to school, where he met Tregear and became his friend. As they went through school together, they also had multiple adventures.

After graduating from school, Taro went on to become a member of the Inter Galactic Defense Force, making it through their training regimen. Tregear tried and failed to join, so Taro urged him to join the Space Science and Technology Bureau.

Taro also watched battle footage of other members of the Ultra Brothers. After Taro successfully absorbed the energy of his parents, he was sent to Earth to defeat Enmargo. Later, Taro would fuse with the other Ultra Brothers and defeat Grand King, causing Juda to go into hiding. After all this, his parents allowed him to become one of the members of the Ultra Brothers.