|“||I wanted to assemble minds curious about the world and eager to improve it, along with the time and circumstance to do so. My desire was to create an elite brotherhood devoted to a new, better civilization. It was naive. Eventually, I was forced to abandon them once I realized I'd cultivated a legion of ego-maniacal sociopaths.||”|
— Elijah on founding The Strix
The Strix is the oldest society of vampires in existence, which was founded in the Middle Ages by Elijah Mikaelson, one of the Original vampires. Until the initiation of Marcel Gerard in the early 21st century, the Strix was made up exclusively of vampires from Elijah's sireline.
Under the leadership of Tristan de Martel, the group expanded into one of the most powerful organizations in the world, responsible for countless wars, assassinations, and plagues throughout history.
Elijah, along with the help of his protege Aya, created the Strix with the intent of gathering great minds in an effort to build a better future. However, Elijah had to abandon the society when Mikael descended upon him and his family. Begging Aya to run with him, he left the Strix behind to be slaughtered by his father. Aya revealed that she did not die due to the efforts of Tristan de Martel, who took over leadership of the Strix. When Elijah returned later that year, he was horrified by the tragedy his father left in his wake, thinking that Aya was deceased, Elijah left his past with the Strix behind.
Throughout The Originals
The Strix are first encountered in I'll See You in Hell or New Orleans, Tristan sends Aya as a representative to Marcel in order to offer him a chance to join them. At first, Marcel refuses, resulting in a fight between them which results in Aya poisoning him and taking him to their meeting place. The meeting is then interrupted by Elijah, who grabs hold of Aya's heart in an attempt to force her to state her intentions. Tristan then arrives in order to diffuse the situation.In A Walk on the Wild Side, the Strix hold a party both so that their members can meet, and as an initiation for Marcel. Tristan tells Marcel that he must find who took has his daylight ring before sunrise, and kill the one who has it. If he succeeds, he's a member of the Strix, if he fails, he dies. Marcel later discovers that, while Aya was the one who took the ring, Mohinder - a vampire of renown battle capability who feeds on the vampires he's about to kill-possesses the ring. The two fight, and Marcel defeats him by tricking him into feeding off of him, and unwittingly taking in the venom of the werewolf bite Marcel had convinced Hayley to give him earlier. However, Marcel refuses to kill him, realizing that the Strix wanted Mohinder dead the whole time. Tristan then kills him, and reveals that whether or not Marcel would be willing to kill him was the true test, and welcomes him into the Strix.
In Beautiful Mistake, Tristan sent a legion of Strix led by Aya, to retrieve Rebekah as part of their plan to bring all of the Originals together so they could trap them all and ensure the vampire species' safety. Aya had trouble finding Rebekah's original body so she killed her as a witch to force her spirit back into its original body. With her witch body dead, the cloaking spell hiding Rebekah's body wore off and she came out of her coffin, surprised by the ambush. She clashed with Aya and the Strix and despite having been in a coffin without blood for six months, held her own, defeating many of the Strix and holding off Aya. However, more Strix arrived. Freya came to Rebekah's aid and snapped all of the Strix's neck with magic, giving Rebekah time to flee. Aya tricked Rebekah into trusting a Moroccan witch and used the witch to keep Rebekah down while she daggered her. They put her body back in a coffin and prepared to send it to Tristan but were betrayed by Aurora, who had members of her own sireline, take the body for her own plans.
Meanwhile, in New Orleans, Shen Min was sent to kill Hayley, so she could no longer protect Davina, who the Strix needed for their plans. However, Shen Min was taken captive by Hayley and Marcel, who Shen Min realized was not loyal to the Strix. After a failed interrogation, Shen Min broke free and prepared to kill them before Elijah arrived and overpowered him. When questioned on what Tristan and the Strix were planning, Shen Min chose to die rather than reveal their secrets, taking off his daylight ring and burning to his death.
In The Other Girl in New Orleans, many members of the Strix go to the Mikaelsons' house to rescue Tristan. Some members save Tristan while others battle Elijah and Hayley, with some getting killed in the process.
In Savior, three members of Strix were sent to retrieve The Serratura from Freya Mikaelson. In the process two of the members were killed by Jackson Kenner but one of them escaped with the Serratura. They also poisoned Freya.
In A Ghost Along the Mississippi, Tristan and the Strix forced Vincent to activate the Serratura in exchange for Freya's pendant containing Finn's spirit. Tristan double crossed Vincent and held him captive with the threat of Finn possessing him again. The Strix take Hayley and Jackson prisoner in a plan to lure the Mikaelsons to a location to imprison them with the dark object. Tristan kills Jackson by ripping out his heart in front of Hayley as revenge for Hayley torturing him. Vincent frees himself with Elijah's assistance and together they kill the Strix escorting Aurora and take her captive. In exchange for his sister and the medallion, Tristan meets the Mikaelsons at their location with an army of Strix to attempt to imprison them once he has his sister. When freeing Aurora, she takes the activated medallion and attaches it to the wall of the storage container their in, trapping Tristan within the impenetrable barrier. After walking out, it is revealed the Freya and Vincent used magic to make Cami look like Aurora, and was unaffected by it's power from being in transition. A horrified Tristan orders the Strix to attack, but Elijah's warnings, and Marcel's advice convince Aya to order the Strix to stand down instead of going to their deaths fighting the Mikaelsons. The Mikaelsons inform Tristan that they will drop the storage container in the sea so Tristan will drown over and over again for all eternity, and effectively remove him as the leader of the Strix.
In A Streetcar Named Desire, all Strix from around the world have come to New Orleans to witness the sirelines of Elijah and Niklaus broken so they can finally be free. While Rayna resurrects once more, she confronts two of the gate guards and kills them. She then makes her way inside and kills several more members while Marcel and Hayley try to rescue Klaus and Elijah.
In An Old Friend Calls, more than a eleven members of the Strix went missing and two members (Isaac and Holt) confront Marcel about it. Near a trash disposal, Marcel meets up with Elijah and he shows him the various dead bodies of the Strix members that were reported missing. It is later revealed that Hayley has been killing the members responsible for her and Jackson's capture. Afterwards, Elijah kills the rest that are on the list and frames Gaspar Cortez as the Strix had dealt with him in the past.
In Alone with Everybody, the Strix feared Elijah's safety after rumors of the last remaining white oak bullet began circulating. They kept a close eye on him and he grudgingly agreed to allow them to guard the Mikaelson compound and put it on lock down, not allowing anyone in or out until the white oak bullet was found.
In The Devil Comes Here and Sighs, several dozen members of the Strix assisted Freya and Elijah in trying to subdue Lucien Castle and protect their sire at all cost. Lucien killed some of them by biting them while those who continued to fight and protect their sire were beaten to unconsciousness or getting their necks snapped.
In The Bloody Crown, Marcel, after becoming The Beast (also called an Upgraded Original Vampire), killed the remaining Strix leaders and members so he could kill Elijah without the Strix army coming to protect him.
In Gather Up the Killers, it is mentioned that Alistair has been tracking down and killing members of the strix to prove Elijah is still alive.
The Strix seek out talented individuals, and help them grow. Their numbers include artists, politicians, warriors, leaders and people talented in many other areas. They also have numerous vampire soldiers under their command.
Notable examples include:
- Tristan de Martel, the first vampire ever sired by Elijah, who is both leader of the Strix and credited by Elijah himself with influencing who he became. He is currently trapped in the bottom of the ocean thanks to the Serratura.
- Aya Al-Rashid, who is skilled in battle and in poisons, being able to create one powerful enough to temporarily take down vampires. She was also Tristan's second-in-command, however, following Tristan's fate, she acted as the leader of the organization for a short while before Marcel took over.
- Marcel Gerard, a vampire sired by Klaus (being the first of his sireline to have membership in the organization) who was able to create a powerful vampire community from the ground up after Mikael's assault on the city, and was able to temporarily be in complete control of New Orleans. He is currently the leader of the organization.
- Mohinder, a warrior who trained himself to go weeks without feeding and feel no ill effects. He fed off of the vampires he was about to kill, and is the one who trained Aya in combat. Unfortunately for him, Tristan became aware of attempts at treachery by him, and so had him killed.
- Shen Min, who was once the great conqueror, Genghis Khan's torture consultant. Shen Min was assigned to remove Hayley from being able to protect Davina Claire. After overpowering his captors, Marcel and Hayley, he was compelled to answer Elijah's questions, but chose to kill himself rather than reveal anymore information, holding on long enough to before his compulsion forced him to answer anymore questions by killing himself in sunlight via removing his daylight ring.
- The Sisters, who are a powerful dark coven of 'lost souls' witches that aid as the personal coven of The Strix. These are outcasts witches without a proper coven or a family who joined The Strix as consultants and personal witches, providing them with spells and predictions. According to Aya, the Sisters possess great skill in witchcraft.
The Strix Charter
In Dead Angels, Elijah crashes a Strix meeting and presents a book known as the Charter — their sacred law book — to Aya, then and current leader of the Strix. Elijah remarks that it has been over nine-hundred years since Aya last saw the Charter, meaning that since the Strix's creation, the Charter has been in the possession of the Mikaelson family.
The Charter is a scroll book containing the sacred bylaws of the Strix, created by Elijah Mikaelson and his protege Aya Al-Rashid over nine-hundred years ago during the creation of the Strix. Each member is bound to the laws and tradition of the Charter despite the fact that many may not know of its existence.
After its inception, the Strix were found by Mikael, and Elijah fled the Strix, taking the Charter with him and leaving his fellow members behind to die for his family. After Elijah fled, Lord Tristan de Martel became the Strix' leader and for centuries afterwards dictated the laws and regulations for the Strix to abide by after abandoning the Charter's teachings.
After the fall of Tristan, the Strix fell under the reign of Aya, co-creator of the Charter. Elijah attended the Strix gathering and reinforced the Charter, making every member of the Strix abide by it — including Aya and himself. Believing that Aya could not properly lead the Strix, Elijah invoked a clause that would restore complete dominion to Elijah himself. In retaliation, Aya invokes on the right of the "Game of Kings" wherein the competing leaders will undergo a contest of cunning and strength of their own choosing (i.e. a duel, a game, etc.) The game was ultimately won by Marcel Gerard, who ascended to the role of leader of the Strix, with Aya and Elijah as advisors.
- Ludum Regale (Game of Kings): A rule that says a member of the Strix can challenge the current leader in contest of either strength or intelligence. The leader is obliged by the law to accept and participate in this challenge and the winner becomes leader. The clause sates: "If our leadership is in doubt and politics proves divisive, a contest of strength and cunning shall determine the line of succession" and whomever holds the charter at the stroke of midnight, will ascend to leadership.
- Sovereignty of the Founding Father: As the Strix was started by Elijah, he holds sovereignty over all over members, including then and current leader. The clause states: "In the absence of a worthy leader, charter shall be invoked, and complete dominion shall be restored to Elijah Mikaelson." 
- Aliquid sub sole: Latin for "anything" and is a famous rite among the Strix. It is assumed than only the current leader can pass aliquid sub sole, if passed, the whole Strix order pledges to fulfill one command.
- Marcel Gerard is the only known leader to ever invoke aliquid sub sole.
- Marcel Gerard (Formerly)
- Tristan de Martel (Formerly)
- Elijah Mikaelson (Founder; Formerly)
- Aya Al-Rashid (Formerly)
- Mohinder †
- Shen Min †
- Holt †
- Takahashi Fukuda †
- Arthur Bailey †
- Cadence Flynn †
- Claire Burnett †
- Isaac Pacheco †
- Robert Craig †
- Emil Blankenship †
- Lawrence Howard †
- Rowan Obi †
- Many Unnamed Members †
*† indicates deceased
- Unnamed Moroccan Witch (Possibly)
- Unnamed Obeah Witch †
*† indicates deceased
- The symbol of the group is of an owl.
- In Greek and Roman mythology, a strix was a bird of ill omen that fed on human flesh and blood.
- Strix is the ancient-Greek word for "owl".
- The cards they give out to recruits reveal the location of where they can be found by covering it in blood.
- The fact that Elijah knew how to reveal the location points to the theory that Elijah had something to do with the creation of the Strix.
- According to Tristan, Marcel Gerard is a potential recruit for the group.
- Aya reveals the qualities they admire in him are that he was able to rebuild New Orleans from the ashes and leading a vampire community through his own hard work, rather than relying on having been turned by an Original Vampire.
- They seem to be rather heavily biased towards Elijah's bloodline, or at least biased against Klaus', as one noted that Marcel was the first potential to ever come from Klaus' line.
- According to Klaus, he had always been excluded from their "club".
- In A Walk on the Wild Side, they organized a Strix Gala where Marcel was invited as a special Guest.
- Tristan de Martel is now imprisoned for eternity due to The Serratura, when his plan to use it to imprison the Mikaelsons for all time backfired, leaving Aya in command for a short while until Marcel took over.
- The Strix has their own dangerous witch coven called The Sisters, who according to Tracy Ifeachor in an interview is the most powerful coven in the world, they apparently possess the power to resurrect the dead without involving nature.
- Although Marcel Gerard led the Strix, they still seemed heavily devoted to blindly following Aya.
- This seemed to be the case under the leadership of Tristan de Martel, given one simple command by Aya, each Strix member fled, forsaking Tristan as their leader.
- They also have encountered Rayna Cruz at some point as Aya knew who Rayna was when she showed up at the house where The Sisters were based in New Orleans. Rayna killed many Strix trying to get to Stefan Salvatore placing them in their own personal hells inside the Phoenix Stone. She was used as a distraction so that Hayley and Marcel could stop Davina along with The Sisters from doing the desiring spell on Klaus and Elijah. They are only half successful as Davina undoes Klaus' sire line.
- The Strix often employed scare tactics, creating a climate of fear to take better control of cities they were infiltrating; often by using serial killings to scare the public. Known serial killers they were said to be responsible for included: Jack the Ripper in England, the Son of Sam in New York City, and more recently, Lucien Castle in New Orleans.
- All the members of The Strix (except for Marcel Gerard) are from Elijah's sireline. It's unknown if all the vampires from Elijah's sireline are members of The Strix.
- In The Bloody Crown, Marcel kills off the remaining Strix in New Orleans.