|“||The three of us spent one hundred years working together and running together.||”|
The Trinity is the name of the group given to the first three vampires ever turned by Rebekah, Klaus and Elijah. As the first vampires turned by the Original vampires, this makes them the three, oldest non-Original vampires in existence.
The Trinity originated from a castle in Southern France belonging to the Count de Martel. Tristan and Aurora were the Count's children while Lucien was a servant at the castle. In 1002, the Original vampires came to the castle posing as nobles; aided by Lucien who helped them with their ruse so they would spare his life. When welcomed into the king's court, they took interest in the Count's children.
Lucien had romantic feelings for Aurora and asked Niklaus to deliver a letter to Aurora in which he declared his love. But unknown to Lucien, Niklaus and Aurora were already in a relationship and were caught by him during an intimate moment. The guards had been alerted by his presence and so to avoid being discovered, Aurora told them to leave through a window. Lucien didn't leave due to the heartbreak of the discovery which led to Tristan believing that he was involved with his sister when he and guards arrived.
As punishment for a crime he didn't commit, Tristan brutally tortured Lucien until he was stopped by Klaus and Elijah. Klaus later attempted to comfort Lucien but he stabbed Klaus and during a brief struggle Lucien came in contact with Klaus' blood. The blood healed Lucien's wounds and he believed that he had become a vampire. In that belief, Lucien proceeded to attempt to kill Tristan but was killed by a guard in the process. He later awakened in transition and fed on a servant, thus completing his transition into becoming the first sired vampire in history. This led the Originals to discover that not only could their blood heal injuries, but that they could also pass on their vampirism.
Niklaus and Aurora continued their secret relationship and when Aurora discovered that he was a vampire she accepted him for what he was. She even asked him to turn her after they confided in each other that they both were responsible for their mothers' deaths. However, Klaus refused to turn Aurora but this did not stop her. She managed to get hold of a sample of Rebekah's blood and once she consumed it, she killed herself through suicide by jumping out of a tower window and awoke in transition having achieved her dream of becoming a vampire.
When the Originals learned that stories had spread of their existence and they would eventually reach Mikael, they planned to flee. Elijah informed Aurora of it and she wished to go with them but Elijah refused. This angered Aurora and she ended up revealing that she knew things about Niklaus which he didn't. In the process of trying to force Aurora to reveal these secrets, Elijah unintentionally used Mind Compulsion, leading to the Originals' discovery of yet another unknown ability of their vampirism. In retaliation for what Niklaus did, Elijah compelled Aurora to see Klaus as a monster, thus leading Aurora to break up with Klaus.
Elijah later sired Tristan and compelled him, Aurora and Lucien to believe that they were the three Original siblings: himself, Klaus and Rebekah and then Elijah told them to run, thus turning them into decoys for Mikael to hunt. The Trinity was hunted by Mikael for a hundred years but were freed from their compulsion when Elijah was daggered by the Five in the early 12th century.
When they were themselves again, they swore to gather weapons to destroy the Originals. However, the deaths of the Original vampires Finn and Kol led to the discovery that if the Originals died, every vampire in their respective sirelines would soon follow suit. To counteract this and also to ensure their own survival, the Trinity shifted their focus from killing the Originals to finding a way to permanently contain them to keep themselves safe.
In light of this, while Aurora was kept in isolation in a monastery as part of Tristan's attempts to control her manic episodes, Tristan and Lucien planned to travel to New Orleans under the pretense of still being mortal enemies, not wanting to raise the Originals' suspicions of their common goal of trapping them.
Throughout The Originals Series
In For the Next Millennium, Lucien arrived in New Orleans to reunite with Klaus. He explained that news of the deaths of Originals, Finn and Kol Mikaelson, and that all of their sirelines died once they did had stirred the vampire community. Knowing that if an Original died, their entire line died, had caused friction that was erupting into a war between the sire lines, wishing to be able to eliminate their rival lines. With the growing threat of the sire war, Lucien tried to align with Klaus, saying they'd have to support each other because all of Lucien's enemies throughout the millennium may target Klaus to try and kill him. Meanwhile, unknown to Klaus, Lucien began a series of brutal murders in New Orleans. He also was somehow involved in the hunting of werewolves in the Bayou. In a faraway monastery, Aurora received a letter from her brother saying he was unavailable to see her which sent her into a fit of rage, saying it was almost time.
In You Hung the Moon, Lucien's killings in New Orleans became known to Klaus and he quickly threatened that if Lucien continued his activities and causing trouble in the city, he'd kill him. Meanwhile, Lucien was suffering from a werewolf bite from Jackson Kenner, but using an unknown injection, seemed to cure himself of the werewolf venom. He then looked at a drawing of Aurora that he had inside of his closet. Meanwhile, in a monastery, Tristan and Aurora sparred with swords when Tristan told his sister that he'd be traveling to New Orleans. Leaving her behind infuriated Aurora and she tried to attack her brother before he sedated her, believing she wasn't ready for the outside world in her mental state. With that, Tristan prepared to go to New Orleans while he left his sister in the care of the monks.
In Where Nothing Stays Buried, Lucien was finally taken down by Klaus, leaving Tristan and Aurora the only surviving members of the Trinity. Both were neutralized, however, as Tristan was trapped at the bottom of the ocean and drowning for the rest of his life, and Aurora was kept asleep via magic.
In Phantomesque, following the death of Elijah's sideline, Tristan too is dead. Given Lucien was also killed at the hands of Klaus, this leaves a sleeping Aurora as the last living member of the Trinity.
- Lucien Castle: The first vampire ever turned by Niklaus Mikaelson and the first sired vampire in history. After spending a century compelled to believe he was his sire, Lucien developed a company devoted to breaking the limits of what was thought to be possible for supernatural research. He formed an uneasy alliance with Tristan to try and trap the Original Vampires so that no harm could ever come to them, or by extension himself. He was later revealed to have manipulated many events in his own favor while the Trinity pursued their goal, leading to his transformation into an Upgraded Original Vampire. Later on, his upgraded vampirism was removed and he was returned to his original state, a non-Original vampire, after which he was then killed by Klaus.
- Tristan de Martel: The first vampire ever turned by Elijah Mikaelson. Tristan was compelled to believe he was Elijah for one hundred years and not long after, took control of Elijah's vampire society, the Strix. Tristan led the Strix for centuries, devising a plan to trap the Original vampires. However, his plan backfired and he was trapped by the unbreakable barrier of The Serratura and was trapped at the bottom of the ocean. Five years later, in 2019, he died from the untimely death of Elijah due to the Hollow.
- Aurora de Martel: The first vampire ever turned by Rebekah Mikaelson. Aurora suffered from something similar to bipolar disorder as a human and after tricking Rebekah to help turn her, it was heightened even more. Her condition grew even worse after being compelled to think she was Rebekah for a century. Aurora, prone to falling into violent and unpredictable episodes, was constantly sedated by her brother, Tristan, who tried to keep her under control. After a number of erratic strikes against the Mikaelsons, her former lover Klaus buried her behind a wall in his home to starve out and desiccate but she was freed by Lucien. Her current status is unknown, following her neutralization with a sleeping spell by Freya.
- Although not yet officially named on the show, the creators of the series have repeatedly referred to the first three sired vampires as "The Trinity".
- Joseph Morgan referred to the three as 'The Trinity' during an interview with Clevver News at the 2016 Comic-con panel.
- The Trinity made their first on-screen appearance together in present time in Out of the Easy, where it was revealed that Lucien and Tristan, and by extension Aurora, were all part of an alliance to try and permanently trap their respective sires so the Originals' deaths would never be a threat to their own lives.
- According to Aurora, the members of the Trinity are immune to compulsion. However, it has not yet been revealed how they became immune.