|“||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 came from a castle in Southern France belonging to Count de Martel. Tristan and Aurora were the count's children while Lucien was a servant at the castle. In the year 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 he caught them during an intimate moment. The guards had been alerted by his presence, so to avoid being discovered Aurora told them to leave through a window, but Lucien didn't leave due to the heartbreak and Tristan believed 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 Niklaus and Elijah. Klaus later attempted to comfort Lucien, but he stabbed Niklaus 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 tried to kill Tristan, but he was killed by a guard, he later awakened in transition and feed on servant which completed his transition into the first sired vampire.
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. Niklaus refused to sire Aurora, but she still became a vampire because Rebekah gave Aurora her blood to save her after she tried to kill herself. Aurora then successfully killed herself and began her transition.
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 and after Aurora bluntly said that she knew things about Niklaus he didn't. He for the first time used compulsion and then forced her to tell him that Niklaus killed his mother. In retaliation for what Niklaus did he compelled Aurora to see Klaus as monster and it lead to Aurora breaking up with Klaus.
Elijah later sired Tristan and compelled him, Aurora and Lucien to believe that they were the Originals that sired them and then Elijah told them to run, thus turning them into decoys for Mikael to hunt. The Trinity were hunted by Mikael for a hundred years, but they 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, after learning about the deaths of Original Vampires, Finn and Kol, the Trinity discovered that if the Originals died, they themselves would die soon after along with their respective sirelines. To counteract this and ensure their own survival, they shifted their focus from killing the Originals, to finding a way to permanently contain them to keep themselves safe. While Aurora was kept in isolation in a monastery suffering through one her 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.
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, and that all of their sire lines 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 eliminated 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 with 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. Lucien, meanwhile 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 travelling 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.
- Lucien Castle: The first vampire ever turned by Niklaus Mikaelson and the first sired vampire ever. After spending a century compelled to believe he was his sire, Lucien has 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 no harm could ever come to them, or by extension himself. He has since broken his truce with Tristan but was revealed to have manipulated many events in his own favor, transforming into an upgraded Original Vampire. Later on, his upgraded vampirism was removed and returned to an average vampire as a result. He was then killed by Klaus afterwards.
- 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 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 has since been trapped at the bottom of the ocean.
- 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 has buried her behind a wall in his home, to starve out and desiccate. She has since been freed by Lucien. Her current status is unknown. However it is possible that she is neutralized, due to the Sleeping curse, as she was last time she appeared onscreen.
- As the first vampires sired by the Original Vampires they are the oldest non-original vampires alive.
- With their advanced age, they may be the strongest vampires in the world besides the Original Vampires.
- Lucien is the oldest member of the group while Tristan is the youngest, however since they were turned within a year, their strength differences would be minimal depending on how strong they were as humans.
- All of The Trinity come from the same home; the castle of Count de Martel. Tristan and Aurora were his children while Lucien was a servant.
- 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 served as some of the main antagonists of Season Three.
- 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.
- Through the compulsion of Elijah, The Trinity spent 100 years running from Mikael believing they were in fact the Mikaelson siblings.
- The compulsion wore off when Elijah was neutralized with the dagger; however, Mikael still hunted them.
- According to Aurora, The Trinity are immune to compulsion, it has not yet been revealed how they became immune.
- With Lucien's death, and Aurora and Tristan's imprisonment, all three of them have been defeated.