- References from numerous sources establish that the various depictions of the mirror universe may not take place in concurrent timelines, meaning there could be a number of divergent alternate reality versions of this topic that do not share the same continuity. The references below this note are separated into subsections to minimize confusion regarding the divergences.
Star Trek: Mirror UniverseEdit
In the timeline of the Terran Rebellion, where the Empire fell and there was no mirror version of the Enterprise-D, the mirror Barclay worked as a field operative for Memory Omega. He served as a 'controller' who assisted his partner, K'Ehleyr, on her missions. (TNG - Mirror Universe short story: "For Want of a Nail")
Barclay and his partner K'Ehleyr later found and recruited Jean-Luc Picard to serve as a buffer between the Terran Rebellion and M'k'n'zy of Calhoun's Romulan Fleet in order to enact Memory Omega's long term plan of freeing the galaxy. Upon Picard's reluctant acceptance of the position, he attained the rank of Captain and commanded the Free Starship Enterprise. Barclay would serve as Chief Engineer aboard the ship and begin a relationship with Deanna. (ST - Mirror Universe novel: Rise Like Lions)
- The source material from the Star Trek: Mirror Universe story arcs does not contradict canon, but does not necessarily share the same continuity as other licensed sources.
Reg Barclay was ambitious and was always told that he would probably be one of the officers that wouldn't get stabbed in the back. Reg graduated top of his Starfleet Academy class in security. Reg served on Starbase 297 as an ensign and assistant body guard to Admiral Nechayev. Reg Barclay hoped to get the position of chief of security aboard the ISS Enterprise, but was beat out by Deanna Troi; however, Captain Jean-Luc Picard liked Reg and made him his chief body guard, even promoting him to lieutenant commander. Troi later vaporized Barclay for letting the Geordi La Forge from the Federation's USS Enterprise-D impersonate his mirror counterpart to thwart an important Imperial mission. (TNG novel: Dark Mirror)
- The source material in Dark Mirror contradicts the canon version of the mirror universe in many ways, meaning this version of Barclay takes place in a very different continuity, most notably different as a reality where the Terran Empire never fell.
Q & AEdit
In one possible permutation of the mirror universe which was encountered through a quantum fissure in 2380, Barclay was an engineer aboard the ISS Enterprise-E, a Terran Empire vessel under the command of Captain Jean-Luc Picard.(TNG novel: Q & A)
|ISS Enterprise-D personnel|
|Reginald Barclay • Beverly Crusher • Wesley Crusher • Eileen Hessan • Geordi La Forge • Miles O'Brien • Jean-Luc Picard • William T. Riker • Mark Stewart • Deanna Troi • Worf|
|ISS Enterprise-E personnel|
|Reginald Barclay • Lore • Miles O'Brien • Jean-Luc Picard • William T. Riker|
|Free Starship Enterprise personnel|
|Reginald Barclay • ch'Sallas • K'Ehleyr • Milioti • Mov • Jean-Luc Picard • Pog • Deanna Troi|