: Shinkoku Nippon invades with giant robots called Garann and gas weapons called Genmu .
: The protagonist and pilot of Shark One. He works as a host to pay off a massive family debt and is initially cynical and hollow. He eventually finds his spark again by motivating the Battery Girls.
: A former underground idol who acts sweet in public but is bossy and foul-mouthed behind the scenes. She fuels Rabbit Two.
The story kicks off in 2019, just as Japan is transitioning into a new era. A rift opens to a parallel world called "Shinkoku Nippon," an alternate version of Japan that maintained its militaristic "Showa" era.
: The primary Battery Girl for Shark One. She is a massive fan of the tokusatsu (superhero) series Zaburn and fights with a hot-blooded sense of justice.