Manga: Choujin Barom 1

Choujin Barom 1 is a manga by Takao Saito that was notably adapted into a tokusatsu in 1972. It revolved around two children, Takeshi and Kentaro, two children given powers by a kind alien Kopuu to transform into the superhero Barom-1 to fight Cosmic Entity Doruge and his minions. More details below.

Later a major influence on Kamen Rider Double.

Choujin Barom 1 provides examples of the following tropes: