Image courtesy of www.henshinhalloffame.com/rainbowman/
Ai no Senshi Rainbowman, or Rainbowman: Warrior of Love, was a tokusatsu series that aired from October 6, 1972 to September 28, 1973 for 52 episodes. It aired on NET (now TV Asahi).
Takeshi Yamoto is kicked off his wrestling team for fighting too violently, and goes to India to seek out Devadatta, a former wrestling champion-turned hermit. He teaches Takeshi discipline, and gives him the power to transform into Rainbowman. Upon recieving these powers, Takeshi immediately flies back to Japan. Whenever Takeshi needs help, Devadatta will show up in Japan.
Rainbowman has seven forms. Moonman (Dash 1) has the ability to deflate and fit into small spaces. Fireman (Dash 2) has the ability to spray fire out of his fingers. Waterman (Dash 3) has the opposite ability of Fireman, being able to spray water or cold air out of his fingers. Leafman (Dash 4) has the abilities of wind and camouflage. Goldman (Dash 5) uses his fingers to shoot lightning bolts. Earthman (Dash 6) has burrowing capabilities, and can create cracks in the earth large enough to swallow his enemies. Sunman (Dash 7) can temporarily paralyze his enemies, form a protective shield, and shoot energy from his fingers. The sunbeam radiated from Dash 7's forehead can be used to produce twin swords. This form is the one used most often by Takeshi, and is the form he uses to transform into his other six forms.
Whenever Rainbowman's wounded, he de-morphs and has to go into a frozen trance to heal himself. This trance, however, leaves him vulnerable to enemies.
The villiains in this series are the Shine Shine Dan (Die Die Army), led by Mr. K. They are a group of foreigners (most of them Chinese), seeking revenge against Japan for the Second World War. Mr. K knows Rainbowman's true identity, and often tries to attack Takeshi's family to get him to surrender. Later in the series, Rainbowman also battles God Iguana (Machiko Soga), who needs his blood to bring her child Iguana back to life (sound familiar, Zyuranger fans?). Her weaknesses are bright light and the sight of her own reflection. From her own blood, she creates two monsters, but when they're destroyed by Rainbowman, she becomes weakened.
The series had an anime adaptation in 1982, which only loosely followed the storyline, making the Rainbowman forms giant robots rather than different costumes.