From the Introduction in the PDF:
The year is 2350.
Knights of the militant holy orders of the Third Reformation Church are locked in a bitter crusade against the Undead, a race of evil beings with necromantic powers and a desire to exterminate all life.
The place is Salus, more popularly called Necropolis, the only habitable world left to mankind since the destruction of Earth in 2319. Divided between the Third Reformation Church, the Union of Corporations, and the Undead, the inhabitants of Necropolis are locked in a struggle for supremacy. Lives are not the only thing at stake; humanity’s very existence hangs in the balance.
If the Undead win, humanity’s light will forever disappear from the universe. Should humanity succeed in overcoming the tide of darkness, it can begin to rebuild its former might, perhaps again reaching out into the void to find new worlds on which to prosper and multiply.