"The Call of Cthulhu" is the central tale in an expanded fictional universe known as the "Cthulhu Mythos." H.P. Lovecraft's friend and protege, August Derleth, coined the term to describe the world in which many of Lovecraft's fictional works take place. Critics tend to treat the "Cthulhu Mythos" as having two components, developed in different stages: first, the cosmological universe that Lovecraft created in his fiction during his lifetime, and second, the later efforts by Derleth and other writers and artists to develop the "Cthulhu Mythos" further after Lovecraft's death.
The first stage of the "Cthulhu Mythos" revolves around the presence of "Great Old Ones," of which Cthulhu is merely one. Other Lovecraft stories that take place in this fictional universe are "The Nameless City" and "The Hound." The second stage of the Cthulhu Mythos, as conceived by Derleth and others, stages the battle between the Old Ones and humanity more explicitly as a contemporary showdown between the forces of good and evil, and categorizes the Old Ones according to four elemental types—air, earth, fire, and water.
The Cthulhu Mythos has also inspired a host of cultural and artistic products, including music, visual art, films, tabletop games, and video games. In 1981, the company Chaosium released a tabletop roleplaying game called Call of Cthulhu, and other popular games like Dungeons and Dragons and Magic: The Gathering have integrated Cthulhu into their expanded universes. From Software's 2015 video game Bloodborne borrows heavily from Lovecraft's fiction, pitting the player against hordes of eldritch beasts. Most recently, in October 2018, Focus Home Interactive released a role-playing survival horror video game called Call of Cthulhu.
