|Dates||August 20, 1890 – March 15, 1937|
|Location||Providence, Rhode Island|
|Episode(s)||6.21 Let It Bleed|
Howard Phillips Lovecraft, also known as H.P. Lovecraft, is a horror writer who opened a door to Purgatory on March 10, 1937. A creature that came through killed him five days later. The murdering creature may have been Eleanor Visyak, though she denies murdering him.
Bobby visits a Lovecraft enthusiast, Judah. When he asks about the date that Moishe Campbell visited Lovecraft, Judah tells him about the dinner party Lovecraft held on that day attended by six friends who Judah describes as "co-worshippers in a black magic cult." They perform a ritual to open a door to an alternate dimension. They think it hasn't worked, but each of them die or disappear within a year. Unbeknownst to them, a creature has come through and possesses Lovecraft's maid Eleanor. Only her 9-year-old son Westborough realizes this, and he is not believed but committed to a psychiatric institution.
- Before demons break into their house, Ben Braeden is reading Cthulhu Tales, a series of comics with stories based in the Cthulhu Mythos. The Cthulhu Mythos is a shared fictional universe created in the 1920s by American horror writer H. P. Lovecraft. Cthulhu is a fictional cosmic entity that Lovecraft created in 1926.
- When Bobby is leaving Judah's office there is a game being played on Judah's television, that game is "Cthulhu Saves the World" an independent game made by Zeboyd Games.
- In Sam's subconscious, he pick's up a copy of Lovecraft's 'The Haunter of the Dark', which stimulates a rush of memory 
- Death also refers to the Leviathans as "The Old Ones" a term used by H.P. Lovecraft in the Cthulhu mythos to describe ancient powerful alien beings who come to Earth.
The Real H.P. Lovecraft
H.P. Lovecraft was a writer of horror and fantasy fiction, who did live in Rhode Island most of his life and died on March 15, 1937 from cancer of the small intestine. While he didn't attain much acclaim while alive, he is now seen as one of the most influential writers of the 20th century. He is most widely known for the Cthulhu mythos, a verse that includes deities who are known as "the Great Old Ones" who once ruled Earth, as well as the Necronomicon, a fictional grimoire.
H.P. Lovecraft was born on August 20, 1890, in Providence, Rhode Island. The horror magazine Weird Tales bought some of his stories in 1923. His story "The Call of Cthulhu" came out in 1928 in Weird Tales. Elements of this story would reappear in other related tales.
In his final years, Lovecraft was barely able to support himself. He took editing and ghostwriting work to try to make ends meet. Lovecraft died of cancer on March 15, 1937, in Providence, Rhode Island. He left behind more than 60 short stories and a few novel and novellas, including The Case of Charles Dexter Ward. Lovecraft's passing was mourned by his devoted following of colleagues and aspiring writers with whom he corresponded and collaborated. Two of these friends, August Derleth and Donald Wandrei, formed a publishing company called Arkham House to promote and preserve Lovecraft's work.
– The Biography Channel website, Source