From the introduction:
This game is about heroes. As a player you take on the role of a hero. Somewhere in the streets of Tokyo a monster—a servant of the terrible Enemy you’ll have to face one day—is going to hurt innocent people. He must be stopped. Luckily you’re not alone; you’re part of an elite team with the power to stand up to the bad guys, to find and extinguish the flame of evil.
This game is specifically about “sentai” heroes. Sentai literally means “fighting team” in Japanese. It calls to mind Toei’s Super Sentai Series of tokusatsu (live action special effects) shows that has been going on since 1975, and Power Rangers, the American adaptation that launched in 1993 and is still going. There are many other titles, tokusatsu, anime, and otherwise, that it inspired, in Japan and elsewhere.