Blade Diver: The Pledge is the story of a young man with intuitive aptitude challenged by a strange other-worldly woman to protect his planet from the harbingers of fire and chaos. The sequel ††et Ero, places focus more on the second Diver, Hellion.
Azur Starrond lives alone in his loft located on the top floor of the tallest tower in the largest city. While he is beginning to believe that there is little point to life, having studied nearly everything the world has to offer, his life is drastically altered when a monstrous creature crashes in a plaza near his loft. Upon examining it in combat with the police, he manages to deduce its weakness, but despite his efforts, he is crushed... literally. He has a dream while recovering in the hospital and awakes in his loft with a young blue-haired woman in his bed who claims to have transported him several hours into the past. A kiss uploads an alien world's entire history and culture and Azur comes to realize he is a prophet and Galax is the scope through which he views the future.
Even after Azur defeats the rock creature, the world is soon threatened by more and more of these monsters until the twin planets of fire and chaos arrive near his world.
Azur Starrond is a 20-something entrepreneur with the ability to understand how things work. He also possesses an eidetic muscle memory, allowing him to duplicate the physical acts performed by others no matter their complexity. He has a compulsion to study, always having a book in his hand.
Galax Black is a demure and enigmatic woman and Azur's "Element of Victory" which allows him to wield "the Sword." Knowing that Azur's natural ability means she doesn't need to explain things in detail, she usually speaks in singular sentences and vague shorthand.
Blade Diver was conceived as a hentai in which the source of the Diver's power comes from physically pleasuring his partner, or Element. While that aspect has not been altogether lost, it now remains only as subtext.