Question: Shadow World is a high-fantasy campaign setting situated on the fictional planet of Kulthea, currently maintained by the primary author of the setting, Terry K. Amthor an American game designer, who has worked primarily on role-playing games, and as a fantasy author, and is of Eidolon Studio, born on which date? 

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Shadow World (role playing game): Shadow World is a high-fantasy campaign setting situated on the fictional planet of Kulthea.  Originally produced for the Rolemaster role-playing game system, the game setting is owned by Iron Crown Enterprises (often referred to as I.C.E.).  It is currently maintained by the primary author of the setting, Terry K. Amthor of Eidolon Studio (who also holds the trademark for Shadow World, and copyrights for non-gaming fiction related to the world).

Forgotten Realms: Forgotten Realms is a campaign setting for the "Dungeons & Dragons" ("D&D") fantasy role-playing game.  Commonly referred to by players and game designers alike as "The Realms", it was created by game designer Ed Greenwood around 1967 as a setting for his childhood stories.  Several years later, Greenwood brought the setting to the "D&D" game as a series of magazine articles, and the first Realms game products were released in 1987.  Role-playing game products have been produced for the setting ever since, as have various licensed products including sword and sorcery novels, role-playing video game adaptations (including the first massively multiplayer online role-playing game to use graphics), and comic books.  The Forgotten Realms is one of the most popular "D&D" settings, largely due to the success of novels by authors such as R. A. Salvatore and numerous role-playing video games, including "Pool of Radiance" (1988), "Eye of the Beholder" (1991), "Baldur's Gate" (1998), "Icewind Dale" (2000) and "Neverwinter Nights" (2002).

Abeir-Toril: Abeir-Toril (or commonly referred to as Toril) is the name of the fictional planet that makes up the "Forgotten Realms" "Dungeons & Dragons" campaign setting, as well as the Al-Qadim and Maztica campaign settings and the 1st edition version of the Oriental Adventures campaign setting.

Campaign setting: A campaign setting is usually a fictional world which serves as a setting for a role-playing game or wargame campaign.  A "campaign" is a series of individual adventures, and a "campaign setting" is the world in which such adventures and campaigns take place.  Usually a campaign setting is designed for a specific game (such as the "Forgotten Realms" setting for "Dungeons & Dragons") or a specific genre of game (such as Medieval fantasy, or outer space/science fiction adventure).  There are numerous campaign settings available both in print and online.  In addition to published campaign settings available for purchase, many game masters create their own settings, often referred to as "homebrew" settings or worlds.

Terry K. Amthor: Terry K. Amthor (born October 18, 1958) is an American game designer who has worked primarily on role-playing games, and as a fantasy author.

Emer (Shadow World): In the Shadow World campaign setting, Emer is a continent on Kulthea, where the Grand Campaign takes place.  It is the largest contenint on the planet, roughly located within the center of the western hemisphere.

Frank Mentzer: Jacob Franklin "Frank" Mentzer III (born in 1950), is an American fantasy author and game designer best known for his work on early materials for the "Dungeons & Dragons" (D&D) fantasy role-playing game.  He was a performing folk musician from 1968 to 1975, and played one concert at the White House during the administration of Richard Nixon.  He was an employee of TSR, Inc. from 1980–1986, spending part of that time as Creative Advisor to the Chairman of the Board, Gary Gygax.  He also founded the Role-Playing Games Association (RPGA) during his time with TSR.  He has been closely involved with the world's largest game auction at the Gen Con game convention since 1983, and is an expert on, and a major collector of, family boardgames and role-playing games.  After Gygax was ousted from TSR at the end of 1985, Mentzer left TSR as well and helped him to start New Infinities Productions Inc. (NIPI).  When this venture failed, Mentzer left the gaming industry, eventually becoming the manager of a bakery.  In 2008, he closed down this business and, two years later, announced he was returning to the gaming industry as a founding partner of a new publishing company, Eldritch Enterprises.

Al-Qadim: Al-Qadim is an "Arabian Nights"-themed campaign setting for the "Dungeons & Dragons" role-playing game.  The setting was developed by Jeff Grubb for TSR, Inc., and was first released in 1992.  Al-Qadim is set in the land of Zakhara, called the "Land of Fate".  Thematically, the land of Zakhara is a blend of the historical Arabian Empire, the stories of legend, and a wealth of Hollywood cinematic history.  Zakhara is a peninsula on the continent of Faerûn in the world of Toril, the locale of the Forgotten Realms campaign setting, although Al-Qadim is designed to stand on its own or be added to any existing campaign setting.  The basic campaign setting was divided between two game products: "", a sourcebook describing character creation rules, equipment, and spells unique to the setting, and "Al-Qadim: Land of Fate", a boxed set describing the land of Zakhara, with separate sourcebooks for the players and the Dungeon Master.

Rob Donoghue: Rob Donoghue is a game designer who has worked primarily on role-playing games. Together with Fred Hicks he created the "Fate system" and has been designer or lead designer of numerous award winning role playing games.  He was a lead designer of the role-playing games "Spirit of the Century" and a designer of "The Dresden Files Roleplaying Game", and has also worked closely with Cam Banks on the Cortex Plus games, a lead designer for "", and as a designer for "Marvel Heroic Roleplaying".  He has also contributed to "Dungeons & Dragons" 4e.

Athas: Athas is the name of the fictional planet on which the campaign setting known as Dark Sun is set, for the "Dungeons & Dragons" fantasy role-playing game.  It is a desert planet, due to the decay of its sun, and overuse of a form of magic (Defiling) which drains the planet's life force.

Supporting paragraphs: Shadow World (role playing game) Terry K. Amthor
Answer: October 18, 1958