So Wolfgang called him Elf Man

The sequel to So Gunther called him Elf Man, blending science fiction, a crime story and history, the novel begins at the conclusion of the first. Set in the near future of 2039 and 2040, but also including back stories over centuries. It is the story of an alien known as the Elf Man (also called Beobachter), and the intersection of the alien's world and Earth in two "Rifts" in space/time. The Rifts are located in Freiburg, Germany and in Box Canyon, California. The Rifts have existed for many centuries, and patrolled by the Elf Man, whose advanced civilization has enabled his extended lifespan.
Wolfgang Grass, the wealthy and influential father of Hans and Franz Grass believes that someone set up the supposed suicides of his sons. Inspector Willy Schreiber, a member of a German anti-terrorism unit is tasked with the investigation. During the investigation, characters from the first book, Professors Dieter Schmidt and Alex Hoffmann are caught up in the unfolding events.
As Wolfgang unravels the fantastic truth of the alien and his follower called "the Wanderer" he spirals into financial disaster and madness, setting in motion events leading to a final confrontation. Inspector Schreiber, with the aid of Dieter Schmidt pursues the criminal trail of Wolfgang in Germany and California.
The sequel includes the origin story of Ahasver, the Wanderer, and the Grass family beginning in the plague year of 1349. One Jacob Gold is abducted by the Elf Man and transformed into a half human, half synthetic being used as a tool by the alien over centuries in pursuing those named Grass.
The alien's twisted attraction to evil personified by generations of the Grass clan propels the arc of the sequel. The inevitable meeting of Wolfgang and the Wanderer ties their stories together, culminating in a final spasm of violence.
Questions of the nature of fate and the human condition in a world increasingly impacted by climate change are explored, notably in the observations of the alien Beobachter and his lieutenant Baithos. A worthy sequel to the first novel.