Thomas Riker

Thomas Riker was a result of a transporter accident in 2361 that created two William Thomas Rikers, genetically indistinguishable from each other, with personality and memories identical up to the point of the duplication. One of the duplicates continued to be known as William Riker. The other chose to use his middle name and be known as Thomas Riker.

Transporter accident
Thomas Riker's life and experiences were the same as William T. Riker's prior to 2361. In that year, William Riker, at the time a lieutenant assigned to the USS Potemkin (NCC-18253), was leading an evacuation mission on the planet Nervala IV. The planet was notorious for its atmospheric distortion field which prevented the use of transporters and shuttles except for brief periods every eight years. During Riker's transport from the planet's surface, a second confinement beam was initiated to overcome these difficulties, with the intent of reintegrating the two beams in the transporter buffer prior to rematerialization on the ship. However, the modulation of the distortion field caused only one transporter signal to correctly materialize on the Potemkin – the second signal bounced off of the field and rematerialized on the planet's surface, unbeknownst to the rest of the crew. As a result, two identical William Thomas Rikers were created. One materialized aboard the Potemkin, and the other was left on the planet's surface, his existence going unnoticed by the crew of the Potemkin. Because the split between signals resulted in an equal distribution of Riker's transporter pattern, both of them had an equally legitimate claim to being the "real" William T. Riker.

The existence of this other William Riker (hereafter referred to as "Thomas") was discovered on Nervala IV eight years later in 2369 when the USS Enterprise (NCC-1701-D) returned to retrieve scientific research that had been left behind. With the aid of Thomas, who had altered the computer systems on the planet to aid in his survival, the Enterprise away team was able to access the information and return to the ship with Thomas.

Relationship with Deanna Troi
During the time he spent on the planet, Thomas had remained deeply in love with Deanna Troi, his girlfriend at the time. Thomas had planned to meet Deanna on Risa the year of the transporter mishap, a fact upon which he had dwelt while stranded. In contrast, the Riker that beamed off-planet eight years prior was soon promoted and made his career a priority over their relationship, and never made the trip to Risa with Deanna.

Upon his rescue, Thomas told Deanna that he could not believe he had failed to meet her as planned and that he was hoping their relationship could resume. Initially, Deanna was opposed to the idea, but found herself won over despite her objections. In the end, however, Thomas decided that he could not remain on the Enterprise, while Troi's feelings for him were not strong enough for her to leave the Enterprise with him.

Divergent personality
Thomas and William clashed almost immediately due to the resentment each felt towards the other. The eight years of living different lives made them entirely different men – William evolved into a cautious and duty-driven officer while Thomas remained impulsive and reckless. As a result of conflicts with William – who was by that time a superior officer (a Commander) – Lieutenant Riker decided to leave the Enterprise. He chose to use his middle name, Thomas, to distinguish himself from his transporter duplicate. Captain Jean-Luc Picard managed to get Thomas a posting on the USS Gandhi where he could continue his Starfleet career. Upon Thomas' departure, William seemed to have accepted Thomas' existence and gave him his trombone as a parting gift. 

Maquis affiliation
In 2370, Thomas expressed dismay at the Federation's policies towards the Cardassians and the Federation colonies in the Demilitarized Zone, and later joined the Maquis resistance. In early 2371, Thomas, posing as William Riker, came aboard Deep Space 9 and stole the newly commissioned USS Defiant (2370).

With Major Kira as his unwilling passenger, Thomas took the Defiant to the Orias system, deep in Cardassian space, where the Maquis believed that the Cardassians were building a fleet of warships. Major Kira accused Thomas of still acting like a Starfleet officer instead of a terrorist; more concerned with intelligence reports and interstellar politics than with simply hurting the enemy. Trying to locate the Defiant with the assistance of Commander Sisko, Gul Dukat swore that he knew nothing of the fleet in the Orias system. He was telling the truth, as the fleet had been constructed by the Obsidian Order in direct violation of Cardassian law. As the Defiant arrived at Orias, it was intercepted by a number of Cardassian warships.

Imprisonment
Sisko achieved a compromise with Dukat and negotiated Thomas' surrender – in exchange for the Defiant's sensor scans of the secretive Orias base, Thomas' sentence would be reduced to life imprisonment in a labor camp on Lazon II, while the Defiant would be escorted back to the Federation-Cardassian border returning the rest of the Maquis crew to the Federation for trial. Thomas was initially wary of accepting the terms offered to him, but Kira pointed out that it would accomplish his mission and let his crew escape Cardassian imprisonment, even challenging his reluctance as some kind of death wish, a desire to go out in a blaze of glory in order to distinguish himself from the other, more successful William Riker.

Immediately after Thomas surrendered the Defiant to the cruisers of the Cardassian Central Command, the Kraxon extended its shields around the Defiant to protect her from the fast approaching ships from Orias (upgraded Keldon class cruisers with markedly higher top speeds than regular ships of its class). Upon seeing this, the ships from Orias – under the command of the Obsidian Order and not technically part of the Cardassian military – turned around and returned to the Orias system.

Just before Thomas transported over to the Kraxon, Kira promised to return for him one day, but it is not known whether she ever did. 

Background
According to the Star Trek: The Next Generation Companion, the TNG writing staff toyed with the idea of killing off Will Riker in "Second Chances," permanently replacing him with Thomas Riker as the new ops officer and moving Data to the first officer position.

Actor Jonathan Frakes, who portrayed both Will and Thomas Riker, described Thomas as being "much less confident than Will. But he's also tender and sweeter. I think I like Tom better". (Star Trek: Deep Space Nine Companion) The DS9 Companion also notes that Thomas' return was on a list of stories the DS9 writers were not interested in hearing pitches on.

In an interview with Jonathan Frakes provided with the TNG Season 6 DVD box set, he states that he had approached Ronald D. Moore regarding a Thomas Riker DS9 episode involving Damar's rebellion. However, this idea was not brought to fruition by the conclusion of the series.

Towards the end of DS9, a rumor that Tom was to be revealed as a member of Section 31 emerged, although Ronald D. Moore said it was not true.

The name Thomas is of Aramaic origin and means twin.

Apocrypha
In John Vornholt's novel , set in 2371, Thomas transferred from the operations division to the sciences division after a conflict with the USS Gandhi first officer. He wore a blue Starfleet uniform and served as a medical courier pilot. It was in this function that he abandoned Starfleet for the Maquis, joining Chakotay and B'Elanna Torres' cell after working with them to stop a dangerous virus. According to Quarantine, it was Chakotay's idea to steal the Defiant from Deep Space 9.

In Peter David's novel Triangle: Imzadi II, also set in 2371, Thomas was freed from the Lazon II labor camp by Romulans, and had a brief affair with Sela, who believed that he was the original Riker. Driven by jealousy over news of Worf and Deanna's recent engagement, Thomas was manipulated into aiding an assassination attempt on Klingon Chancellor Gowron and Emperor Kahless, but it was averted due to Odo's interference, as Riker and Worf managed to replace the bottle that Thomas had been given – he had been told it contained poison that would only kill Gowron but it actually contained a dangerous nanovirus that would annihalate the Klingon race – with Odo. Thomas managed to escape capture, but his actions actually strengthened the Klingon-Federation alliance; believing the bottle to be poison, Thomas had been prepared to drink it himself before Gowron, thus prompting Gowron to reflect that there was still value in the alliance with the Federation if even a discredited Starfleet officer was willing to sacrifice himself for the sake of their alliance. This novel also featured some reflections on Thomas's reasons for abandoning Starfleet, including the idea that he sees himself as an 'alternate' for Riker; having witnessed what Riker became as a loyal Starfleet officer, he decided to find out for himself how he would do as something else.

In the Malibu Comics Deep Space Nine title, two stories were published extending Riker's story. "Sole Asylum, Part One" and "Part Two", set at the end of 2371, showed that Riker had been taken to Cardassia Prime and that Cardassian scientists were trying to discover the secret of his duplication in order to create an army of duplicates. It was also revealed that Riker's cells were only nine years old, suggesting their complete creation at the time of the accident. Unable to rationalize the accident against the Law of Conservation of Mass and proven transporter theory, one of the scientists, a Dr. Nol, told the Cardassian High Council that he must be from an alternate dimension. Because of this, the Council decided to send him back to a labor camp.

In the computer game Star Trek: Deep Space Nine - Dominion Wars, set between 2372 and 2374, a Federation Alliance mission involves rescuing Thomas from a Cardassian convoy, after which point he is available as a commander for your ships. A Dominion mission in the same game requires the player to destroy the starship under his command.

In Judith and Garfield Reeves-Stevens' novel series Millennium, an alternate timeline found Thomas rescued from the labor camp by the Grigari. Feeling abandoned by Starfleet, Thomas joined the Bajoran Ascendancy, although he secretly worked as a double agent for Starfleet. By 2399, he was the commanding officer of the USS Opaka and was killed on Christmas Day of the same year after failing to kill Kai Weyoun. This timeline was later reset thanks to Benjamin Sisko and the crew of Deep Space 9.

The eBook "A Weary Life" revealed that, shortly before the events of, Will Riker still felt betrayed by Thomas' actions in stealing the Defiant. In a conversation with Deanna Troi, it was revealed that Thomas had left the USS Gandhi and her crew to join the Maquis. Thomas had been recaptured by the Cardassians after the attempt to assassinate Gowron, and had been returned to the labor camp on Lazon II. All of these feelings had Will questioning his inclusion on a mission to the DMZ assigned by Picard. The feelings came to the surface again when Will met with Kalita and discovered that Thomas had allowed himself to be captured to save his Maquis conspirators. Discovering this led Will to feel pride for his "twin," the first positive feeling he'd had since Thomas joined the Maquis.

In Star Trek Online, Thomas' son Joshua Riker can be met in the Badlands. He explains that the labor camp was eventually abandoned and that his father had led the survivors to build a community. Thomas died several years later of heart failure while carrying his critically injured wife back to camp where she died.

According to the Star Trek: Titan novel Fallen Gods, it was commonly believed by 2382 that Thomas Riker had died while in Cardassian custody during the Dominion War.