The Great Demon Lord Is Too Weak to Cock

The Great Demon Lord Ecchitis Manjiras...
A beautiful woman with huge breasts and a plump ass, she lead legions from Hell on an invasion of Earth!
Against her unstoppable magic power, human nations fell left and right!
Humanity was ready to throw in the towel! Everywhere you went, you'd hear them shout: "It's hopeless", "It's all over...", "Save us, Hero!"
However... This unstoppable woman had a shocking weakness, and behind the scenes, the army of the Demon Lord had quite the big problem of their own...