Battle Fever J

Battle Fever J holds the distinction of being the first series to officially launch under the "Super Sentai" moniker. It was produced as a co-production between Toei and Marvel Comics following the massive success of their 1978 Spider-Man tokusatsu adaptation. Initially, the series was conceived as Captain Japan, intended to be a localized version of Marvel's Captain America before evolving into its own unique team format.

The story begins when the sinister Secret Society Egos launches an offensive, with their first order of business being the assassination of top-ranking officials within the National Defense Ministry. To combat this threat, General Tetsuzan Kurama assembles four elite young agents who had been dispatched around the globe for specialized training. They are joined by Diane Martin, an FBI investigator seeking vengeance after her father was murdered by an Egos assassin. Equipped with advanced powered suits representing different countries, these five agents unite to form the Battle Fever team.

As the conflict escalates, Egos attempts to halt the construction of the team's most valuable asset, the giant Battle Fever Robo. After their initial monsters are defeated, Egos deploys the younger brother of the Buffalo Monster, a towering giant robot replica. Fortunately, the Battle Fever Robo is completed just in time, allowing the team to destroy the mechanical beast and the giant successors that follow.

The team endures heavy casualties during the war, losing both the original Miss America, who is forced to return home after a severe injury, and the first Battle Cossack, who is tragically killed in action. Joined by new members who take up the fallen mantles, the Battle Fever team ultimately defeats Commander Hedder, who is transformed into the Hedder Monster, and breaches the Egos headquarters.

In a final desperate trap, the team is nearly fed into the Egos Monster Making Machine to be converted into a Battle Fever Monster. They manage to destroy the machine and, utilizing the devastating Lightning Sword Rocketter sword-throwing technique, finally slay the mysterious deity Satan Egos, bringing an end to the secret society.