The hero known as Secret was once an ordinary girl named Greta Hayes. She was murdered by her adoptive brother, Billy, who would later become the supervillain known as Harm. Because of the manner of her death, Greta remained stuck on this plane of existence, a gateway between the living and the dead.
In her first appearance, Secret was being held against her will by the DEO. Robin, Impulse, and Superboy helped her to escape, and were able to convince her to join their crimefighting team, "Young Justice," at the same time as Wonder Girl and Arrowette. Being incorporeal, Secret is able to take on a variety of appearances, and is referred to as "the mist girl" or "the bottle girl" by the various agents who pursue her throughout her career.
Her brother Billy assumed the villainous identity of Harm and attacked Young Justice, but died when his own father shot him. Billy returned during the events of "Day of Judgment," when the entirety of Hell had been evacuated. He again battled the team, using the substance of Secret.
Before her real name was known, Secret was often referred to as Suzie. Secret became good friends with the two girls, and was often portrayed as shy. For awhile she nursed a crush on Robin, and often defended his actions and followed his leadership unquestioningly. She also often expressed jealousy of Spoiler, Robin's girlfriend, to the point where the pair of them once had a full out battle across Gotham City, only stopped by the combined efforts of both Red Tornado and Robin.
During the Sins of Youth event, a temporarily adult Secret, with the aid of Deadman, chased down Klarion the Witch Boy's cat familiar Teekl, as Klarion had been overtly threatening them. Surprising her age-altered friends, she caused Klarion to back down by threatening to kill Teekl. When undoing everything he had done, Klarion insisted that it was everyone or nothing. Secret didn't want to change back to a kid, but was persuaded to by Robin, who promised to always be there for her. As predicted by Merry Pemberton, this would later cause many problems. Secret would even go so far as to physically threaten Spoiler.
At one point Hal Jordan, the Spectre, tried to mentor Secret. During this time, she visited her father in jail. Under the mental influence of "Billy," her father rejected her, leaving her more despondent than before.
Secret eventually gave in to the darkness in her nature at the behest of Darkseid, whom she mistakenly referred to as "Doug Side." During her time on Apokolips, Billy possessing her father, launched the body into one of the firepits, killing them both. Although Hal Jordan offered to step in and save Greta, as well as the world, the current Young Justice team advisor, Snapper Carr, rejected the offer, preferring that the kids use Secret turning evil as a "learning experience." Robin was eventually able to talk her down by himself. Towards the end of Young Justice, a disgusted Darkseid stripped Greta of her powers, and left her an ordinary, living girl, which was, ironically, just what she had always wanted to be.
Greta now attends the Saint Elias School for Girls, with schoolmates Cassie Sandsmark (Wonder Girl) and Cissie King-Jones (the former Arrowette).
- Warder Physiology: When Greta was killed by her brother, she was able to stay on the earthly plane as a warder, someone who guides spirits who have just died to the afterlife. She has an ethereal body with a unique power set.
- Flight: As an ethereal being, Secret can levitate and fly through the air at will, although she seems to be able to allow herself to be subject to gravity.
- Intangibility: Secret typically remains in an intangible state. Solid matter and some forms of energy have been able to pass through her body without causing her harm. Secret is, however, susceptible to electric and magic-based attacks, even though she is mostly intangible. Secret can actually make herself solid for up to a few minutes at a time, allowing her to touch other objects (and hit enemies).
- Sublimation: Secret is visually comprised of a smoky, misty quasi-ethereal substance. She can turn her body partly or wholly into smoke. As smoke, Secret has complete control over herself, able to travel through the air as she desires. She can perceive her environment while in this smoke form, even though she often has no discernible eyes or ears or whatnot. She has forced her gaseous body into the air passageways of enemies to disallow them to breathe, making them pass out.
- Smoke Construct Creation: Much like how she can make her normal-looking body solid for brief periods of time, Secret can make the smoke she produces/becomes form into solid constructs. She has made a cage before, and she has used her smoke to throw enemies and catch falling allies.
- Metamorphosis: Secret can alter her form to look like whatever she wishes. She still retains the same color scheme, but the shape can be changed to make her look like other things. One of her favorite alternatives to her human form is a dragon-like monster with fangs and claws, but she has altered her appearance in other ways as well. Much like her normal form, Secret seems to be able to make herself solid while in these other shapes as well.
- Superhuman Strength: When Secret shape-shifts parts of her body into shapes that give her strength. For example, she has shape-shifted her fists into large, stone-hard fists that were able to greatly crack the concrete she punched.
- Superhuman Durability: Secret can shape-shift parts of her body into a denser form. She has once turned her hands into a wall to protect her teammate from danger.
- Size Alteration: While altering her appearance, Secret can make herself larger than her standard human size. Her dragon-like monster form tends to be a quite large, and she has transformed herself to look like a several-stories-tall version of a certain politician.
- Teleportation: Secret has the ability to "smoke jump," as she calls it. Using this ability, she can teleport herself and/or others in a puff of smoke. She has been able to travel considerable distances with her smoke jumps.
- Dimensional Travel: In addition to her ability to teleport, Secret has the ability to bring others into a pocket dimension that only she has been shown to be able to access. Calling this place "the Abyss," Secret has brought in friends into her dimension to protect them from danger, and she has pulled enemies within the Abyss as a form of confinement. Inside the Abyss is pure darkness, unless Secret herself appears to communicate with her prisoners. The Abyss is somehow inside of Secret, part of her being.
- Fear Projection: The pocket dimension known as the Abyss has the innate ability to create fear and other negative feelings within the people inside. She has accidentally almost traumatized her friends when she briefly pulled them inside to protect them, but she has also intentionally used this ability to scare enemies.
- Magic/Supernatural Sense: Secret was able to detect the magical energy signature of Klarion and track him down. Furthermore, she can also see spectral entities that usually cannot be seen, line Deadman.
- Death Sense: Secret can sense when death is about to happen, and she can sense when death has just occurred.
- Self-Sustenance: Secret does not appear to need to eat, drink, or breathe, although she has been sleeping at times.
- Clairvoyance: By turning into smoke and entering the body of the dying Kathy Sutton through her air passageways, Secret was able to "mingle" in a sense with Kathy's soul, which was preparing to leave and enter the afterlife. While the experience seemed like a dream, Secret was able to coax Kathy into staying among the living. Secret could presumably do this for others if she had the time and the person in question likewise had the realistic potential to stabilize.
- Possession: By forcing herself into the air passageways of someone, Secret was able to control that person's body. Not only was she able to control the person's movements, she was able to speak through the person and was able to access that person's metahuman powers.
- 93 Appearances of Greta Hayes (New Earth)
- 33 Images featuring Greta Hayes (New Earth)
- 4 Quotations by or about Greta Hayes (New Earth)
- Character Gallery: Greta Hayes (New Earth)
Young Justice member