Question: Who published the system that includes D6 Space?

Context paragraphs:
Barry Reese: Barry Reese (born November 11, 1972) is an American writer.  He is best known for his work on "The Official Handbook of the Marvel Universe" for Marvel Comics, "D6 Space: Fires of Amatsumara Worldbook" for West End Games and his pulp adventure universe series of novels.  He is married to artist Cari Reese and together they have one son, Julian Reese.

Star Wars: The Roleplaying Game: Star Wars: The Roleplaying Game is a role-playing game set in the "Star Wars" universe, written and published by West End Games (WEG) between 1987 and 1999.  The game system was slightly modified and rereleased in 2004 as "D6 Space", which used a generic space opera setting.  An unrelated "Star Wars" RPG was published by Wizards of the Coast from 2000 to 2010.  Since 2012 the official "Star Wars" role-playing game is another unrelated game, published by Fantasy Flight Games.

Iron Kingdoms: Iron Kingdoms is a fantasy role-playing game, originally published by Privateer Press on July 1 of 2004 for the d20 System, with several supplemental books released in following years.  On July 1 of 2013, Iron Kingdoms was newly released under a unique d6 rules system closely based on the rules for the miniature war games Warmachine and Hordes from which the Iron Kingdoms RPG is derived.  The setting combines high fantasy and steampunk genres into what Privateer Press warmly describes as "Full Metal Fantasy".

D6 Space: D6 Space is a generic science fiction role-playing game (RPG) based on the "D6 System".  Although derived, in part, from material originally presented in "The Star Wars Roleplaying Game", "D6 Space" is published as a stand-alone rulebook (not dependent upon or requiring other D6 System or Star Wars rulebooks) and is supported by its own line of supplements.

General Quarters (rules): General Quarters is a set of naval wargaming rules written by Lonnie Gill.  Quick and easy to play they have become one of the most popular series of World War I and World War II era naval rules (they topped the poll of popular wargames rules amongst the Naval Wargames Society.  There are currently three versions available.  GQ1 covered World War II and used a d6 based system.  GQ2 expanded coverage to World War I whilst also introducing new rules for World War II games; it also introduced a revised combat system that used a d10 in addition to d6.  GQ3 was a complete revision published in 2006.  A revised World War I version was announced for release in September 2007, and published as Fleet Action Imminent . There are a number of campaign supplements for GQ3.  First is The Solomons Campaign about the World War II Guadalcanal battles.  Next is Sudden Storm a hypothetical campaign dealing with a war, between Japan and the US in 1937.  A surprisingly possible occurrence, and one that yields a lot of big gun battles as the US fights its way back across the Pacific to the Philippines.  All in a very smooth and playable format.

D6 System: The D6 System is a role-playing game system published by West End Games (WEG) and licensees.  While the system is primarily intended for pen-and-paper role-playing games, variations of the system have also been used in live action role-playing games and miniature battle games.  The system is named after the 6-sided die, which is used in every roll required by the system.

Star Trek Roleplaying Game: The Star Trek Roleplaying Game is a role-playing game (RPG) set in the "Star Trek" universe using the "CODA System" rules and first published by Decipher, Inc. in 2002.  When Decipher acquired the rights to create the RPG, they also acquired most of the gaming studio from Last Unicorn Games.  However, the Decipher game system is dissimilar to .  Instead, the system is similar to Wizards of the Coast's "d20 System" but uses 2D6 to resolve actions.

D6 Fantasy: D6 Fantasy is a generic fantasy role-playing game (RPG) based on the D6 System.  D6 Fantasy is published as a stand-alone rulebook (not dependent upon or requiring any other D6 System rulebook) and is supported by its own line of supplements.

Space Racers: Space Racers is an American CGI animated television series featuring the cadets of the Stardust Space Academy.  The series premiered in 2014 on Maryland Public Television and was distributed through American Public Television (APT).  The show formerly aired reruns on Sprout.  The show follows the Space Racers Cadets as they travel our Solar system on fun and exciting missions of space exploration.  The show includes science and technology components as part of an early childhood STEM curriculum, receives input from NASA on science and space technology, and also maintains partnerships with the U.S. Space & Rocket Center and its Space Camp.

D6 Adventure: D6 Adventure is a generic role-playing game system based on the D6 System.  "D6 Adventure" is published as a stand-alone rulebook (not dependent upon or requiring any other D6 System rulebooks) and is supported by its own line of supplements.

Supporting paragraphs: D6 Space D6 System
Answer: West End Games