|Native Inhabitants||Humans, cats, zebras, kelp|
|Greyhawk Powers||Baba Yaga, Green Man, Olman pantheon|
Earth, also known by such names as Gothic Earth, is a fictionalized version of the "real" world that interacts on several levels with the world of Oerth.
There is more than one alternate Earth. Some are magical, at least subtly, and some are not. In his essay "Chronomancy & the Multiverse," Roger E. Moore said that the world of the "Historical Reference campaign" series was the same as the world of the Masque of the Red Death campaign setting and the province of Averoigne in module X2, Castle Amber (which is in turn the world where the stories of Clark Ashton Smith and H.P. Lovecraft are set). He suggested the Gamma World setting might be a possible future of this world.
In a 1984 interview for Polyhedron Newszine, Gary Gygax revealed several "alternate Oerths" while explaining the setting for his Heroes Challenge game books, co-written with author Flint Dille and published under the aegis of the Dungeons & Dragons Entertainment Corporation by the Wanderer Book division of Simon & Schuster.
"By the way, action takes place on Yarth, a place somewhat similar to Oerth, the setting of Greyhawk, et al. It has fewer magical properties than Oerth but more than Earth. It is not impossible that additional works will be contracted for in months to come, action being set on Yarth or perhaps another alternate world, Aerth. On Earth, magic is virtually non-existent. On Uerth, dweomers are weak, chancy things. Yarth has a sprinkling of things magical, and Oerth is pure magic."
Other references to these alternate Oerths appear in the Gord the Rogue short story anthology Night Arrant as well as in Gygax's Epic of Ærth campaign setting for the Dangerous Journeys roleplaying game.
The five parallel worlds of Oerth—Oerth, Aerth, Uerth, Yarth, and Earth—were mentioned in the 3rd Edition adventure Expedition to the Ruins of Greyhawk and thus found their way into 3rd edition canon.
Emigrants from Earth to Oerth
- Baba Yaga is a witch-like character from Russian folklore. Her adopted daughters Iggwilv and Elena the Fair may also be from Russia, though as her hut travels between worlds this is by no means certain.
- A myth published in Dragon #358 suggests that the mortal Saint Cuthbert was brought to Oerth from another world by Rao. The fact that there was a historical St. Cuthbert of Lindisfarne (c. 634–20 March 687) has not gone unnoticed, either, though it's not clear if Greyhawk's Saint Cuthbert is intended to be the same person or a namesake who became a saint during his time on Oerth.
- The crashed spaceship in Expedition to the Barrier Peaks came from another universe, presumedly one in which a future version of Earth exists.
- The Green Man of Sybarate was originally part of the Old English mythos, summoned to Oerth by the wizard Porpherio.
- The gods of the Olman are said in Deities & Demigods (1980) to exist on a parallel Prime Material Plane. In Legends & Lore (1990), these gods are said to live among the stars and planets surrounding a world with a fantastic version of Earth's Central America.
- According to Dragon #82, perytons are originally from the lost continent of Atlantis. They traveled to other worlds using psionics, a Talent they slowly lost on alternate planes.
- In Andre Norton's novel Quag Keep and its sequel Return to Quag Keep, a group of gamers from Earth end up in the bodies of Oerth natives.
- The Rhennee originated in a place they call Rhop, which might be a corrupted form of the word "Europe." If so, they might originally have been gypsy-folk from Earth.
Visitors from Oerth to Earth
- The wizard Ardraken discovered a cola machine while visiting a parallel world, and returned to Oerth with a simulacrum of it.
- The adventure "The City Beyond the Gate" in Dragon #100 implied Saint Cuthbert had come to a nonmagical version of Earth in 1932 AD to hide the Mace of Cuthbert in the Victoria and Albert Museum in London. This adventure also describes a temporal distortion between Oerth and this Earth, such that 1932 to 1985 in Earthly time translates to over 640 years of Oerthly time.
- Gord the Rogue visited contemporary Earth in the short story "Evening Odds," which appeared in an anthology of fiction inspired by Michael Moorcock's Eternal Champion mythos. In that story he allies with a Los Angeles street gang in order to combat an invasion by the fiendish lord Baphomet.
- Iggwilv has a portal to a world based on Greek mythology in the Lost Caverns of Tsojcanth. In his article "Gates in the World of Greyhawk," Roger E. Moore suggests she may have gone there to recuperate and regain her powers after her climactic battle with Graz'zt.
- Iggwilv is known as Louhi on one Prime Material world, presumably an alternate Earth where the events of the Kalevala literally took place.
- Mordenkainen visits Ed Greenwood's house in Canada in the "The Wizards Three" series in Dragon Magazine. In WG7, he travels to Hollywood to get a movie deal.
- Murlynd, a traveler through many planes, has taken to dressing like an inhabitant of North America's "Old West" period. His house in The Land Beyond the Magic Mirror contains many Earthly artifacts, such as a VCR. In that module, his name is followed by the initials F.K.O., M.L.G.T.S.A, which according to Gary Gygax in the Oerth Journal #12 stands for "Fellow of the Khans of the Orient (our local SAC for a time)" and "Member Lake Geneva Tactical Studies Association." In "Chronomancy & the Multiverse," Roger E. Moore says that Heward has collected items from various periods in Earth's history as well.
- Neb Rentar and his party were transported by a cursed scroll to the starship Warden, a generation ark with origins on Earth.
- In the Urban Arcana and Shadow Chasers campaign settings for the d20 Modern RPG, the Plane of Shadow is simply known as Shadow. Due to an unknown reason, creatures from other material planes can be randomly ripped from their current plane of existence, and deposited on Earth with no memory of their previous home, and fluency in the local language (which is always the same as Common). This is called The Gift of Lethe. While their memories of their former lives are gone, they sometimes remember their former deities, and thus Oerthly gods such as Wee Jas, Pelor, and St. Cuthbert have become worshipped by groups on Earth. In the Urban Arcana setting for d20 Modern, Wee Jas's worshippers are called "The Beloved," and hide behind a very selective national fraternity and sorority of business and management majors, known as Epsillon Alpha.
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