04 - Swordsman of Lost Terra by Poul William Anderson

In the haunting world of Lost Terra, Kery of Broina roams like a restless spirit, driven by a desperate quest to reclaim the powerful resonant pipes of Killorn—an ancient weapon of the gods. As he approaches the citadel of Earths forsaken, he must confront the echoes of madness that threaten to consume him. Experience a gripping tale from the masterful Poul Anderson, as the fate of the world hangs in the balance.