Der Dagon Zyklus by Wolfgang Hohlbein

In a world where ancient myths and modern realities collide, a group of unlikely heroes embarks on a perilous journey to uncover the secrets of a long-forgotten civilization. As they delve deeper into the mysteries of the past, they encounter mythical creatures, hidden realms, and dark forces that threaten to unravel the very fabric of their existence. With time running out, they must harness their courage and wit to confront an unimaginable evil and prevent an impending catastrophe that could change the world forever.