The Saga of Tanya the Evil, Vol. 9 (light novel)

The Lergen Kampfgruppe has retired from the front lines at last, returning to the
capital to rest and resupply. There, all they see is stagnation and an overwhelming
hunger for victory. And all too soon, the next impossible mission is already slated,
involving more inventions of a certain mad scientist. All that lays before Tanya is
darkness, but this is one quagmire even she cannot escape!