The Keep (1983)

From cover:

Long before the pyramids in Egypt were built, two demi-gods were locked in a struggle to decide the fate of manking. Throughout the centuries, the necromancer Molasar made unholy war against the people of Earth. To sate his evil needs, he was responsible for hundreds of disasters and wars including the Black Death!
Then in 1476, the forces of light imprisoned him in THE KEEP, a magically protected fortress. But 500 years later, in April 1941, a small band of German Wehrmacht soldiers occupied THE KEEP and unsuspectingly disturbed the Evil One's forced slumber. The battle begins again and you are invited to join the struggle at...

THE KEEP

THE KEEP is a faithful and detailed fantasy roleplaying adventure based on the major Paramount Picture's film release of the same name.
Not only will it pit you against the forces of death and evil, but also against the might of the German S.S. THE KEEP features a new set of rules and charts that lets you include modern weaponry and tactics in fantasy adventures. It is designed for three to six characters from ninth to twelfth level and is suitable for use with all popular roleplaying systems including Advanced Dungeons and Dragons*.

• Advanced Dungeons & Dragons is a trademark of TSR Hobbies, Inc. Use of this trademark is NOT sanctioned by the holder.