One of the biggest differences between DC Comics continuity and the Young Justice TV series can be found on Mars. Unlike most versions of the DC Universe, the Mars of Young Justice remains home to a thriving, advanced civilization of White and Green Martians, each far from extinct — though it is suggested throughout the series that Green Martians may enjoy a higher social status than their White counterparts.
One such citizen is M’gann M’orzz, a young Martian with an affinity for superheroics and Earth culture… and who holds a few deeply guarded secrets.
Shortly after Robin, Kid Flash, Aqualad and Superboy found their own team, Martian Manhunter of the Justice League introduced M’gann to the group as his niece. Going by the codename “Miss Martian,” M’gann quickly established herself as integral to Young Justice by providing a psychic link between members for communication. Although Superboy initially mistrusts her ability to peer into his mind, he soon came to see her as not just a teammate, but a romantic interest.
On a mission to Bialya, Miss Martian had her first battle against Psimon, a telepathic agent of The Light, where she restored the blocked memories of her fellow teammates. And when M’gann and Superboy go undercover to infiltrate Belle Reve Penitentiary, their romance blossomed as they shared their first kiss.
Months later, on a mission to Qurac, Young Justice met Marie Logan, a retired actress who looks remarkably like M’gann in her human identity. They soon learn that M’gann based much of her appearance and personality on episodes of an old, unsuccessful sitcom called Hello, Megan! Under duress, M’gann admitted she had been hiding her true Martian form. She also assisted Marie’s son, Garfield Logan, after he’s hurt in an explosion by transmuting her own blood to match his rare blood type — an incident which we later learn may have triggered his metagene. But it’s not long before Queen Bee, one of the leaders of The Light, attempts to blackmail M’gann over her true identity, as revealed to her after M’gann’s psychic battle with Psimon.
M’gann wrestled with this dilemma for a while, but ultimately chose to put her faith in her team. Before Queen Bee can use her secret against them, she voluntarily revealed that she had been a monstrous White Martian this whole time, using her shapeshifting abilities to masquerade as a Green Martian. Once again, Young Justice proved their loyalty by accepting her for who she is, and together they launched a crucial assault against The Light.
Five years later, we find Miss Martian still with Young Justice, now dating new member Lagoon Boy. We also find her having accepted the role of a foster sister to Garfield Logan, now serving as the changeling Beast Boy, after his mother Marie was tragically killed by Queen Bee.
Later, Superboy admits that he pushed M’gann away during the interim over his own crisis of identity. Left hardened by Superboy’s rejection, M’gann throws herself entirely into her missions with Young Justice, to a dangerous degree. When they are tasked with uncovering and repelling an alien invasion of Earth, M’gann begins to “brain blast” enemies and captives for information — a process which proves effective but leaves the interrogated party comatose.
The ethics of this technique finally catch up with M’gann when she uses her brain blast on a turncoat Aqualad, who to her horror she discovered had been playing double agent for Young Justice this whole time. With Aqualad comatose and hospitalized, M’gann vowed to never probe another mind again. Eventually, fellow team member Artemis helped M’gann find redemption by encouraging her rediscover her heroic roots, and restore Aqualad’s mind.
M’gann and Lagoon Boy eventually broke up over the realization that she still harbored feelings for Superboy — feelings which were rekindled when the couple reunited after defeating the invasion of The Reach.
Two years later, Miss Martian functions as the new team leader, now fully embracing her White Martian heritage in appearance. When M’gann expresses her concern over Superboy joining up with Nightwing’s renegade team of Outsiders, he confirms the importance of their relationship by proposing to her — which M’gann accepts.
Later, M’gann took a few members of Young Justice with her to aid the New Gods, who have been framed for an attack on the Bugs of New Genesis. To her dismay, M’gann learned that her own brother, Ma’alefa’ak, was behind the deception. Ma’alefa’ak confessed to M’gann that he was now working as part of the alliance between Darkseid and The Light, in an attempt to secure a better future for the oppressed White Martian race. With the battle between Young Justice and The Light now a family matter, the extent of Miss Martian’s future involvement remains to be seen.