Complex sentence: Poelzig lives in a mansion on the site of the battleground, built on the ruins of the old military fortress Marmarus, where the two men play strange games for the lives (and the souls?) of a young couple.
Split into simpler sentences: Poelzig lives in a mansion on the site of the battleground, built on the ruins of the old military fortress Marmarus. There the two men play strange games for the lives of a young couple.