In the year 1670, to get away from the newly established British rule, a man named Gerrit Martense, and his Dutch family, built a house on Tempest Mountain, in the then remote Catskill Mountains. As time went on, the Martense family eschewed outside contact and began to inbreed among themselves. One distinguishing feature that all Martense family members had was their eyes. One was blue, the other was brown.
However, what no one realized at the time was that the Martense family was in possession of a copy of De Vermis Mysteriis, a rare book that told of the Old Ones. The Martense family believed that the Old Ones would one day return.
In the 1750's, Jan Martense broke with his family and ventured out into the world. He was the first member of the Martense family to do so in decades.
However, when he eventually returned to the Martense house on Tempest Mountain, the rest of the family apparently murdered him for his daring to leave. The family was then completely ostracized by the outside world from that point on.
The Martense family disappears from view
In 1816, an investigation was launched into the fate of the Martense family, who had not been seen in decades. The house was found to be deserted and it was assumed that the family had either moved away or died off.
However, what no one realized was that, after generations of inbreeding, the Martense family had degenerated into subhuman creatures that now lived in tunnels that they had dug throughout Tempest Mountain. In the years that followed, they began to abduct people. They did this for fresh breeding stock, to keep their family line going.
Quinton Able encounters the Martense family
In 1922, Quinton Able, a ‘connoisseur in horrors’ decided to investigate the strange events surrounding Tempest Mountain. During Able's investigation, two men, George Bennett and William Tobey, mysteriously vanished, and a third, a reporter named Arthur Monroe was murdered. All were victims of the Martense family.
Able continued his investigation and finally discovered the terrible truth about the Martense family. In the end, he had the old Martense house blown up, in the hope of destroying the degenerate family. However, he was only partially successful. The Martense family survived and continued to abduct people, only they were more cautious about how they did it.
Rex and Hannah encounter the Martense family
In 2015, shortly after their move to Arkham, Massachusetts, Rex Buckland and Hannah Webster travelled to the Catskill Mountains to investigate the disappearances that had taken place at Tempest Mountain over the last few centuries. They were worried that the planned building of a new hotel resort and ski lodge there might endanger innocent lives of the future patrons of that resort.
Although they initially believed that the Mi-go were responsible for said disappearances, Rex and Hannah soon uncovered the truth, the degenerate Martense family was responsible. The former Warlocks were captured by said family.
By then, due to centuries of inbreeding, the Martense family had become creatures that looked like deformed apes with matted fur and sharp yellow fangs. Rex realized who the creatures were because of the unique feature of the eyes of the Martense family, one being blue, the other being brown.
The family matriarch, Johanna Martense, explained to Rex and Hannah that they were preparing for the return of the Old Ones and showed them their copy of De Vermis Mysteriis. The book, Johanna claimed, instructed the family to breed among themselves as part of said preparation. Rex and Hannah were then locked up, as both were viewed as potential breeding stock.
Realizing that the Martense family had to be stopped, Rex and Hannah escaped and soon returned with dynamite and gun powder. Rex then attempted a last ditch appeal to Johanna, to try and convince her to change the family’s ways. When that failed, Rex and Hannah were forced to use the explosives to finally destroy the Martense family and their copy of De Vermis Mysteriis.
However, Johanna alone had survived Rex and Hannah's attempt to wipe out her degenerate family and vowed to keep trying to find a way to free the Old Ones. She then formed an alliance with the ghost of Herbert West (after using a spell from her destroyed copy of De Vermis Mysteriis to make him corporal) to achieve that goal.
Freeing of Hastur
In 2017, Johanna and West travelled to a South Pacific island, that Johanna had raised using her magic. This island contained the Old One called Hastur, who was resting in a state of suspended animation.
Despite the presence of Rex, Hannah, and Randolph Carter, Johanna and West managed to transport Hastur away from the island and succeeded in awakening him. Thus their goal of freeing the Old Ones is one step closer.
The Lurking Fear by H.P. Lovecraft
Rex and Hannah Chronicles Story No. 35: The Legacy Of Tempest Mountain
Rex and Hannah Chronicles No. 40: The Secret Of The House
Rex and Hannah Chronicles Story No. 46: The Island