The Keep (1983)

The Keep (1983) Nazis are sent to guard an old, mysterious fortress in a Romanian pass. One of them mistakenly releases an unknown force trapped within the walls. A mysterious stranger senses this from his home in Greece and travels to the keep to vanquish the force. As soldiers are killed, a Jewish man and his daughter (who are both knowledgeable of the keep) are brought in to find out what is happening.