- For the Gideon operating on the Waverider, see Gideon (Waverider).
- For the artificial intelligence operating on the Wellenreiter, see Wellenreiter Artificial Intelligence.
Gideon is an interactive artificial consciousness (A.I.) used by Eobard Thawne. She was hidden in the Time Vault inside S.T.A.R. Labs. Though Gideon is used by Eobard, she was created by Barry Allen in the future. In order to manage her operating system, one needs the Reverse-Flash ring.
In the hands of Thawne
Thawne used Gideon during his travels to the past to fight future Flash.
After he ran back in time to the year 2000 chasing Barry Allen, Eobard was told by Gideon that his connection to the Speed Force was no longer present and that he couldn't travel back in time to his home, leading him to steal Dr. Wells' identity.
Gideon's operating system was later installed in Thawne's hidden Time Vault in S.T.A.R. Labs at some point before or during 2013. On December 11, 2013, Gideon was activated in response to the appearance of 2018 Barry Allen. Accompanying Barry was his future daughter Nora, whom Gideon identified as XS and noted was the fifth recruit of a group called the Legion, only to be interrupted by Barry, who ordered her to recalibrate the Speed Force transmitter he inserted into its console to extract dark matter from the impending particle accelerator explosion and to leave no record of this.
Thawne used Gideon to record and catalog his notes about Barry Allen since he was struck by lightning and his heroics as "The Flash" ever since. He later used it to search for the Flash in future newspapers after his abilities were repressed by Blackout, to no avail. After Barry regained his abilities, Gideon was able to find the Flash in an article from 2024, reporting his disappearance in the crisis.
When Firestorm was about to go nuclear, Eobard entered his secret chamber (Time Vault) to retrieve a gun to shoot Firestorm. Gideon remarked that the weapon was rather crude. Thawne then had a change of heart and asked Gideon if the tachyon device could be converted into a quantum splicer. Gideon answered that it was theoretically possible, but doing so would delay his timetable.
When Barry, Cisco, and Caitlin discover the Time Vault, they met Gideon, who identified Barry, mentioning his future position as director of CCPD's CSI division and a founding member of something, but was interrupted by the latter before it could name the group. Barry then asked Gideon if it knew Thawne's true identity, but Gideon failed to understand his question. He then changed the question, asking what the Reverse-Flash was doing in their time. Gideon answered that he wanted to kill Barry as a child but the latter escaped, so he killed Barry's mother Nora out of anger. He then asked what Thawne wanted from him but Gideon only said that the endgame was Barry to be the Flash. As Thawne approached, Cisco feared that Gideon would tell him of their discovery, so Barry asked Gideon if it could show them its operating system to erase its memory. However, Cisco took one look at Gideon's operating system and realized he couldn't do it, so Barry asked Gideon hesitantly to keep their meeting a secret. Gideon agreed, and much to the astonishment of Barry, explained that it was he (Barry) who created Gideon. As Barry whisked himself, Caitlin, and Cisco, out of the room, Thawne entered and was casually greeted by Gideon. He asked if everything was alright, and Gideon said that everything was fine.
After Team Flash discovered Reverse-Flash's true identity, Thawne deactivated Gideon for safety purposes, presumably to avoid the Flash using her against him.
Three years later (exactly 1078 days later), she was activated once again, this time by Harrison Wells from Earth-2. Gideon asked him how can she help, and Harry said that a lot has changed in the last three years.
Gideon is later hijacked by Clifford DeVoe using Kilg%re's powers, enabling him to hijack S.T.A.R. Labs' satellite to replace one of five that Barry destroyed for his Enlightenment. He also plugged in a vial of dark matter and Neil Borman's former miniaturized cell-turned nuclear fusion battery into her console to transmit the energy to the satellites.
After Nora became a member of Team Flash, she kept in contact with Eobard Thawne (that was somehow imprisoned in Iron Heights in 2049) through her journal, with Nora sending information to Eobard's cell through Gideon's limited time travel capabilities in regards to information, using a specific form of "time text", that is supposed to survive through the changes of timeline.
- It identified the languages in the time vault to detect intruders.
- It is assumed that Gideon was inactive in the Time Vault until Harry reactivated her in "".