Born into royalty from an aquatic dimension called Xebel, Mera entered Earth's dimension and formed a partnership with the hero Aquaman that quickly blossomed into love. Greatly loved by both her husband and her people, Mera rules the kingdom with a firm but just hand that is rarely seen amongst the nation's various intermittent rulers.
Mera was born the older princess of Xebel; an extra-dimensional penal colony that an ancient group of separatist Atlanteans were banished to from behind a sealed portal in the Bermuda Triangle. Trained as an infiltrator and killer since birth alongside her younger sister, Hila, Mera was sent by the King of Xebel through a small fissure in space-time to Earth on a mission to confront the current King of Atlantis and kill him in retaliation for their exile.
Operating on the cover story that she was once the Queen of "Dimension Aqua" and that several years ago a criminal named Leron seized control of the kingdom and exiled her from her kingdom, Mera "fled" to Earth whereupon she met the Atlantean sea-king, Aquaman. Convinced of her story, Aquaman vowed to assist Mera in any way possible. When Leron "pursued" Mera to Earth and captured her along with Aquaman, he brought them back to "Dimension Alpha" where they were imprisoned. Aided by the water sprite known as Quisp, Aquaman managed to free Mera and defeated Leron. However, rather than return to the throne of her kingdom, Mera elected to return to Atlantis with Aquaman.
As Mera continued to share in adventures with the sea-king, the pair began to fall in love despite her mission and the two were soon wed, with Mera living with Aquaman as Queen at the Atlantean Royal Palace. However, Mera never revealed her true origins, deliberately choosing to keep her cover story to avoid frictions with her love. Soon after, they had a son named Arthur Curry, Jr., also known as Aquababy.
Less than two years later, Black Manta, who had a vendetta against both Aquaman and Mera's family in Xebel, kidnapped Arthur Jr. and trapped him inside a translucent tank designed to suffocate him due to lack of water. While Aquaman manages to defeat the villain, Arthur Jr. fell into a coma. Believing him dead, Aquaman went on a mission of vengeance while, back in Atlantis, it turned out that Arthur Jr. had not died from suffocation and was being kept on life support by Vulko. As her child's health declined, Mera returned to Xebel to find a device that could save her child, although instead she was forced to depose the regime that Leron had established as dictator in her absence. As Mera single-handedly defeats Leron and his elemental monsters in order to retrieve the device her quest proves successful but by the time she returned home with the device, it was too late and she was faced with the agony of her son's death alone.
As Aquaman returned in the middle of the funeral, Mera tried to kill him for not being there when their son needed him most, believing that his super-heroics and revenge were more important to him than his own family. They were interrupted by a villain named Sea Quake who almost destroyed the city with destructive sonic waves, although he was revealed to be a mindless robot. Ocean Master had been controlling the robot to create a fissure in the ocean floor, diving down to retrieve an ancient Atlantean super-weapon. Aquaman defeated him alongside Aqualad and Mera, and the family seemed together again although their son's death created a rift between Aquaman and Mera.
The couple tried relocating to a flooded city on America's East Coast to start a new life together but it was during this time that Aquaman left to reform the Justice League in Detroit. Becoming more unstable with rage over her grief and the constant pressure of maintaining her cover, Mera suffered a nervous breakdown and abandoned her husband, blaming his "weak genes" for her baby's death; citing that had her son been born of a man from her dimension, that he would have been strong enough to survive Black Manta's attack. Their marriage dissolved, Aquaman left Atlantis but Mera stayed behind as her mental stated continued to deteriorate until finally one of the kingdom's interim rulers had her committed to the AHARD-1 mental health facility.
Mera remained at the hospital for several months until an alien force of giant jellyfish took control of the city. During Aquaman's battle to free the Atlanteans, Mera escapes the facility and savagely attacks him. While defending himself, he accidentally pushes her on an upturned piece of metal. Believing her dead, Aquaman had her placed inside a coffin and taken to the royal palace, however, she survived due to her alien physiology and, rising from her coffin, she bitterly reminded Aquaman of how little he really knew of her. No longer seeing any reason to remain on Earth, Mera left Atlantis and returned to Xebel.
Mera later returns from Xebel now believing herself to be a Navy marine biologist named Miriam Bridgeman. After Arthur demonstrates her true identity through a series of physical tests, Mera is revealed to be under the control of the dimension's current Queen, V'lana, and tries to strangle Aquaman. After Mera is freed after they travel back to her dimension, they fight Queen V'lana and defeat her. Given the choice to succeed V'lana as the dimension's Queen, Mera abdicates her throne and returns to Earth to be with the man she loves.
However, soon after Mera is lured into the hellish realm known as Netherspace, where she was captured and brainwashed by Thanatos; an evil mirror-universe "clone" of her husband. Approximately nine months after she was taken, Mera gave birth to a second son, naming him A.J..
When Mera finally returns from Netherspace, she walks in on Aquaman consummating his relationship with a woman named Dolphin. While Mera inexplicably fights Dolphin, she is revealed to have been brainwashed, whereupon Aquaman follows her into the other dimension and finds her with Thanatos. After Mera and AJ break free of Thanatos' control, Aquaman does battle with Thanatos before an evil judgment tribunal known as The Others, but when he refuses to kill Thanatos the judges decide to condemn Aquaman to remain in the realm while Thanatos is free to be Aquaman in the New Earth universe. Aquaman prays to his father, Atlan, who hears his call and opens a portal through which the family can escape. However, A.J.'s body was not accustomed to the passage of time on Earth and begins to age at an accelerated rate. Noticing this, Mera grabs her son and leaps back through the closing portal, abandoning her recently reunited husband to be with her son, ending up in another realm called Oceanid.
As Mera became the realm's new Queen and A.J. grew up to be the realm's hero and defender "Aquaman", alien invaders called the Maritorn came to steal the water from their world. Returning to Earth to seek Aquaman's help, but due to his magic protection that stopped his rapid aging, A.J. had difficulty keeping his mind clear and began believing himself to actually be Aquaman. When he got to Poseidonis he found the real Aquaman and challenged the "pretender". When Aquaman inevitably defeated him the magic protection wore off and A.J. began to rapidly age again. Recognizing who he was, Aquaman returned with A.J. to Oceanid too defeat the invading aliens.
With victory in hand, Aquaman was once again reunited with Mera and he begged her to return home with him but due to being the Queen of the realm and having a son unable to leave for Earth, she insisted on staying. However, as Aquaman left and wanting to see his parents happily together, A.J. suddenly pushed her through the closing portal, giving her no choice but to return to Poseidonis as A.J. remained to be the realm's sole ruler and hero.
As Mera and Aquaman eventually reconcile, they return to live in the renamed city of Atlantis and continue to have adventures together, including a trip to Skartaris, where they team up with the Warlord, Travis Morgan. They appear to form a true royal family along with Tempest and his wife, Dolphin. Mera participates in the delivery of Garth and Dolphin's son, Cerdian, during this peaceful time. Unfortunately, while attempting to fight an Imperiex probe during Imperiex War, Aquaman causes a probe to self destruct over Poseidonis. When Tempest, in a desperate bid to save everyone, transported them 3,000 years backward in time, they are captured by the exiled Atlanean sorceress Gamemnae and enslaved for 15 years, with Aquaman being converted into a water spirit and trapped within a pool of water. Freed and returned to present time by the Justice League, Mera announces that there must still be a reckoning for the destruction and fifteen years of slavery and Aquaman is put on trial by his own people for high treason.
Following Aquaman's exile, a despotic sorcerer named Hagen becomes the nation's prime minister and gains control of Mera through a mixture of narcotics and sorcery, forcing her into a coma as Atlantis is been taken over by his own sorcerers trained in the Obsidian Age.
While Mera manages to break from her coma, she remains sick and Aquaman leaves his duties at Sub-Diego to be by her side; fighting through Atlantis' defenses in order to do so. Discovering that Hagen's sorcery had caused Mera to develop lungs, Aquaman takes her to Doctor Anton Geist in Sub-Diego for treatment, but Geist was turned into an OMAC before he could help her. In an effort to undo Hagen's sorcery, Tempest gathers the most powerful Atlantean mages together and saves Mera, but this also attracts the attention of the Spectre during his rampage to wipe out all magic.
Following the Infinite Crisis, Mera leads a faction of Atlanteans in rebuilding Atlantis, which was destroyed by the Spectre during the crisis.
- Mera appears in Gotham during the Valentine's Day Event and upon interacting with her, rewards players with a Message in a Bottle item, when opened provides a collection to the Collections: The Royal Relationship.
- Initially thought to be behind the Atlantean attack on Metropolis, it was revealed that the "Queen Mera" commanding the Atlantean armies was actually Circe in disguise; having infiltrated and gained control of the Atlantean royal family, including Aquaman. After you break Circes grip on Aquaman she and Aquaman go back to tend to Atlantis.
- Mera appears in Central City Starro Deluge Zone where she requests your assistance in investigating the root cause of Starro 's appearance in Central City to work alongside The Flash and eventually herself and Aquaman in Deluge.
- Mera first appeared in Aquaman #1 (October 1963).
- Mera's original appearance in DC Universe Online was originally similar to that of the Remora armor style, however, as of Game Update 79, Mera's look was updated to her 2017 "Rebirth" appearance.
- Mera has the ability to manipulate water by creating "Hard Water" constructs. She has been shown to use her water manipulating ability to lift and move water around her, as well as using it to create concussive blasts of water and water/weapon constructs.
- Exposure to lead will rob Mera of her hard-water powers.
- While A.J.'s true father could easily be either Orin or Thanatos, it is assumed to be Orin.
- Though not overtly visible, Mera possesses a set of gills which allows her to extract oxygen from the surrounding environment enabling her to breathe underwater. Mera can also breathe in an oxygen/nitrogen atmosphere, but only for limited periods of time.
- Mera also possesses a limited degree of telepathy, which allows her to communicate with other Atlantean beings.
- One of Mera's favourite dry land foods is ice cream and banana splits.
- While briefly operating as a superhero alongside her husband, Mera took on the name "Aquawoman" and donned a female variant of his costume. While she has long since retired from superhero work, Aquaman keeps her outfit in the lighthouse for "personal reasons".
- Mera is voiced by Deena Hyatt.