Kekkou Kamen

The superheroine protector of Sparta Academy's students who fights in the nude, covering only her face, arms and legs.
Her signature finishing move is the "Oppiroge Jump" (おっぴろげジャンプ), which involves her jumping on her opponent's face groin-first.

Her real identity isn't a single person, but a group of six different women - anytime one of them gets exposed, the rest provide each other with an alibi.

Note: Initially created by Go Nagai as a joke pitched to his editor, being a parody of the first Japanese tokusastsu superhero, Gekkou Kamen.