- For the Supergirl episode, see "".
- "All I know is that whenever the three of you show up, it usually means we have one huge problem."
- —John Diggle on the Trinity[src]
Although the members of the Trinity met each other countless times since 2013, the first time all three members met up was when Barry Allen and Cisco Ramon traveled to Earth-38 to recruit Kara Danvers in order to get her help with the Dominator invasion, which resulted in the Kryptonian meeting the heroes of Earth-1, including Oliver Queen. However, the three heroes didn't officially team up until the Nazi invasion a year later.
Crisis on Earth-X
After discovering that the New Reichsmen, a squad of Nazi soldiers from Earth-X were trying to steal a solar energy device in Central City, the Trinity went to confront them. While Flash and Supergirl arrived at the scene within moments thanks to their super-speed, it took Green Arrow longer to get there, breaking the awkward tension by reminding the two of them that he doesn't have powers. The Trinity was soon confronted by Dark Arrow, Overgirl and the Reverse-Flash. It later turned out that Dark Arrow and Overgirl were actually Oliver and Kara's doppelgangers from Earth-X, and that the Reverse-Flash was Eobard Thawne of Earth-1.
After a short conversation, the Flash faced off against his arch-nemesis while Green Arrow shot Overgirl with a Kryptonite arrow and Supergirl used her super-breath to knock her down. Acknowledging their eventual defeat, Overgirl used her heat vision to damage a local construction site, putting all of its workers in danger. using this to distract the Trinity while they made their escape. Luckily, The Trinity managed to save the workers by having Flash speed them out of danger. Supergirl held the support structures in place and Green Arrow used his cable arrows to stabilize the building. After that confrontation, the three returned to S.T.A.R. Labs to meet up with Sara Lance, Mick Rory, Martin Stein, Jefferson Jackson, Alex Danvers, Team Flash, and Team Arrow to plan their next move.
With the help of their teams, The Ray, Leo Snart, and the rest of the Legends, The Trinity was successful in defeating their doppelgangers and Thawne in one final confrontation, albeit losing Professor Stein in the process. After Stein's funeral, The Trinity parted ways again once Kara and Alex Danvers headed back to their Earth.
After John Deegan was gifted the Book of Destiny by Mar Novu, he accidentally swapped the lives of Oliver Queen and Barry Allen. Looking for a way to undo this, the two traveled to Earth-38 to ask for Kara's help. After Kara helped Oliver and Barry to realize they need to act like each other, the Trinity was greeted by Cisco Ramon, who asked them for help with defeating a super-powered android called A.M.A.Z.O., which they agreed to do.
The Trinity, along with Superman, went to fight A.M.A.Z.O. and after an intense fight, succeeded. Back in S.T.A.R. Labs, they figured out their next move to return everything to normal is to travel to Gotham City and find the man who altered reality.
When the Trinity headed to Gotham City, Barry and Oliver debated the existence of Batman, with Oliver adamant that he was the first vigilante superhero, and that Batman was just an urban myth created by the local police. Once they arrived, Barry and Kara once again waited for Oliver to catch up to them, even though he was now the fastest out of the three of them. They planned their next move, which was to locate Vesper Fairchild, a reporter who slept with Oliver once and may know the whereabouts of the Doctor. After being unsuccessfully mugged ("unsuccessfully" due to Kara catching a bullet meant for Oliver and Barry using Oliver's abilities to disarm and incapacitate the thugs' leader), they were all thrown in jail. However, they were bailed out by Kate Kane. In exchange for them leaving Gotham as soon as possible, she gave them the intel and resources needed to find the Doctor, whose name turned out to be John Deegan.
The team, along with Cisco, John Diggle, and Caitlin Snow managed to get into Arkham Asylum. However, Deegan discovered this and released all the cells from his office, triggering a prison-wide riot and using it to escape capture. The riot kept the Trinity and friends busy, needing to spring into action to contain it. It slowly ended up proving to be too much to handle once they encountered Nora Fries with her husband's freeze gun, Roger Hayden, and a hallucinogen that caused Barry and Oliver to see each other's worst fear. The overwhelming circumstances led to Kate Kane needing to suit up and reveal herself as Batwoman to save them. With Kate's help, Oliver and Barry were quickly knocked out of their condition, they were able to retrieve the Book of Destiny from Deegan, and the Trinity was on their way back to Star City, much to Kate's appreciation, although she did begin to warm up to Kara.
The Trinity got close to uncovering the book's secrets until they got interrupted by the appearance of the Barry Allen of Earth-90. He warned the team that this reality swap was all a test set up by Mar Novu. The intention was to put the greatest heroes of every Earth in a dimension-shattering reality and see if they can prosper, the goal being to find those capable of saving the multiverse from an oncoming crisis. This debrief was halted by Novu teleporting into the streets of Central City. The Trinity and the older Flash confronted Novu, but he simply teleported the older Allen away and the Trinity all got separated by John Deegan when he used the book again to make a new reality where he is Superman and the Trinity are all criminals.
After freeing Kara with the help of this Elseworlds' version of Cisco, the Trinity was once again reunited with the real Superman and began planning the means to fix reality and stop Deegan. They got a plan together, but according to Superman, it would cost the lives of both Kara and Barry. The two were shocked, but then realized they have no choice and decided to continue with their plan. Luckily, Oliver prevented their demise by making a deal with Novu: he will fulfill the multiverse's requirements and in exchange, Novu will give him the means to save Barry and Kara. Novu accepted it and gave Oliver the means to save them from death via a cosmic arrow. After saving Earth-1 from Deegan, Kara and her allies returned once again to their Earth.
In 2019, The Legends needed marketing for their theme park to help unite humans and magical creatures after the demon Neron revealed their existence to the modern world. Sara Lance, Nate Heywood, and Time Bureau Agent Gary Green posed as Kara, Oliver, and Barry respectively for a promotional video that was shot by Bureau Director Ava Sharpe and Zari Tomaz. Zari asked if it would have been better if the real Trinity was there to help but Sara replied that they passed on it, likely due to the Legends choosing to avoid helping with the Elseworlds issue.
- Mar Novu/The Monitor
- Clark Kent/Superman
- Kate Kane/Batwoman
- Lois Lane
- Team Flash
- Team Arrow
- Freedom Fighters
- Harrison "Harry" Wells (returned to Earth-2)
- Harrison Sherloque Wells (returned to Earth-221)
- Barry Allen/The Flash (status unknown)
- Zari Tomaz (history with Legends erased from existence)
- Amaya Jiwe/Vixen (returned to 1942)
- Rory Regan/Ragman (left until he can restore his bond with the rags)
- Curtis Holt/Mr. Terrific (left to go to Washington D.C.)
- Alex Danvers (status unknown)
- Dominators (retreated)
- New Reich
- John Deegan (incarcerated)
- Mar Novu/The Monitor (turned ally)
- A.M.A.Z.O. (destroyed)
- Roger Hayden (incarcerated)
DC's Legends of Tomorrow
- "" (with Superman)
- This team includes the main protagonists of all the live-action Arrowverse shows (outside of , which doesn't have a clear main protagonist, and the retroactively added and ).
Behind the scenes
- In the DC Comics, The Trinity is a group of superheroes made up of Batman, Superman, and Wonder Woman.