"My name is J'onn J'onzz. I am the sole survivor of a ravaged world. I will not see the same thing happen to Earth."
A Martian who was accidentally teleported to Earth by Professor Erdel, J'onn J'onnz assumed the guise of recently deceased detective John Jones in order to fight crime on Earth, and conceal himself from humanity. Outed by villainous Martian B'rett, J'onn joined the JLA, serving with them until his home planet was destroyed by Commander Blanx. Locating his few surviving people, J'onn tried to help them build new lives on Mars II, but was driven out by The Marshal, eventually rejoining the JLA.In the Post-Crisis world, Mars was retconned into having been devastated decades ago, and J'onn's time on Earth was lengthened considerably; he was now one of the few superheroes to have been operating from the 1950s until the dawn of the Modern Age. A founder and core member of the JLA, Post-Crisis J'onn is regarded as the "heart and soul" of the team.
Combo Platter Powers: His power list could be considered this, but make more sense when you consider that all of his abilities (with the possible exception of martian vision) stem from his psychic powers or shape-shifting.
Creepy Good: Although one of the most kind and noble heroes in the DCU, J'onn's glowing red eyes and stoic demeanor could scare some people.
Darkand Troubled Past: Probably the most extreme example in the DCU (and that's saying a lot), as he witnessed the fiery death of his entire species, wandered the ruins of his home planet for an untold amount of years and was transported to a strange alien world (Earth) by accident.
Expy: Was originally one for Superman, though as time has gone by the two have become increasingly different, with much of Silver Age and Bronze Age Superman's alien pathos having been passed to J'onn.
New Powers as the Plot Demands: Had this bad in the silver age, from straining gold from seawater, to seeing in to a future which will not happen to manipulating the earths magnetic field to walk on water. Has been toned down since, but is still a living Swiss Army knife.
Personality Powers: Averted with his shape-shifting, as he is very calm and serious. Played straight with his telepathy.
Weaksauce Weakness: Fire. How bad it is, and whether it is psychosomatic or not varies, but it is always a problem.
A police officer who served as John Jones' partner in the Silver Age, and as a member of his detective agency in the Modern Age, making her one of his few supporting cast members to have any sort of staying power.
AKA: M'gann M'orzz/Megan Morse
"I don't want you hurting any more Earth people. That wouldn't be nice."
A White Martian with a conscience, M'gann M'orzz joined Earth's Teen Titans' while pretending to be another surviving Green Martian. She is something of a protege for J'onn, serving as a surrogate niece to him.
Cute Bruiser: Looks like a cutesy teenage girl. Hits near as hard as J'onn himself.
Weaksauce Weakness: Has the usual Martian problems with fire, but even more exaggerated, losing control of her form and dissolving when exposed to flame.
"To protect myself I started a war..."
A Bronze AgeFemme Fatale who encountered J'onn J'onnz on several occasions, Bel Juz was a treacherous Desert Dweller (Green Martian), who sold out her surviving people to Thythen invaders, in the aftermath of Commander Blanx's attempted genocide. When the Thythen were defeated, Bel became involved with The Marshal of the Red Brotherhood, encouraging his invasion of Earth in a desperate attempt to cover up her involvement in the near destruction of her people.
Blondes are Evil: While her hair was lilac in her first appearance, it was blonde in her second.
Small Role, Big Impact: Bel only appeared in two Bronze Age stories, but her manipulations ruined J'onn's political career, and were responsible for him rejoining the JLA. Without her, J'onn's current role as "heart and soul of the JLA" might never have come about.
Smug Snake: Never quite as bright as she thought she was, and with a penchant for backing the wrong horse.
One of the DNAliens created by Cadmus Labs, Bette Noir is a hideous, immobile blob, incapable of leaving the laboratory in which she is imprisoned. She does however, have one thing going for her—the ability to project her consciousness out of her body and feed on the psychic energies of others. She clashed with J'onn a couple of times during his Post-Crisis, Pre-Flashpoint incarnation.
The leader of the Pole Dwellers (Silver and Bronze Age precursors to today's White Martians), Commander Blanx was a cold-blooded opportunist who aimed first to conquer, then to enslave, and then finally, to annihilate, all Martian life, in a bid to sell the planet to an offworld mining corporation. Restarting the war between the Pole Dwellers and the Desert Dwellers, Blanx exiled his rival, J'onn J'onnz to the wastes, seized control of Mars, and then finally harnessed the Blue Flame of Mars to slaughter Pole Dweller and Desert Dweller alike. Killed in single combat by J'onn he has not appeared since.
Archenemy: During the Bronze Age, and retroactively, J'onn's entire Post-Crisis career, being the one who started the war between the Desert Dwellers and Pole Dwellers, exiled J'onn to Earth, triggered the formation of the JLA, saw Martians ostracized on Earth, and finally, massacred everyone J'onn cared about, including his family. For all that his appearances were limited, Blanx's influence, and the effect that he had on J'onn, would be hard to top.
The Big Bad: Of "And So My World Ends", the story that redefined Martian Manhunter, creating the version of the character that we all know today.
Cowardly Lion: Blanx didn't like to fight, preferring to let others do it for him, but when he's finally cornered he proves a capable enough combatant, beating J'onn in their trident duel and nearly killing him.
"You let Mars burn! And Mars will forever smolder with the fire of your failure!"
An alien tyrant who came into conflict with the JLA when he pursued two rebels to Earth, Despero has a long and ugly history with the Martian Manhunter, dating back to early in his conflict with the League. Reborn several times into a greater and greater engine of destruction, Despero lives for revenge against the League, with J'onn J'onnz at the top of his hit list.
Archenemy: To J'onn. While he's officially an enemy of the League as a whole, he truly despises J'onn and will go out of his way to kill him first whenever the League shows up. This is largely because J'onn is responsible for some of his more bitter and humiliating defeats, making him the one whom Despero, in his own words, "hates most of all." J'onn for his part fears and hates Despero right back, and the two have fought every few years from the 1960s into the present day, making them one another's longest running, most persistent, and most personal foes.
The Dreaded: Anything involving him is an "oh shit" moment. When he shows up, holding back is not an option, and it always takes multiple teams just to slow his progress. A single team going up against him is a suicide mission.
Evil Counterpart: It's not as obvious as some, but Despero, with his history of isolation, longevity, religious ties, status as a leader on his world, Psychic Powers, and connection to fire is, at the end of the day, an evil version of J'onn J'onnz which is what makes the rivalry work. More on that can be found here.
Motive Decay: Initially he was an alien despot looking for escaped rebels hiding on Earth. Then it was because he wanted revenge on the Justice League for humiliating him front of his subjects. As he got more-and-more powerful, this came up less-and-less. By the time he stole the United Nations' flag to use as a cape, it'd been essentially forgotten.
Power Of Hate: He is driven by unadulterated rage - tempered by a certain amount of cold cunning and pure hatred. Martian Manhunter once defeated him by using his mental powers to make him hallucinate killing all the heroes, at which point he declared he was satisfied and let go of all his hate and anger, regressing to a baby. Unfortunately, when he found out he had been tricked, his hate and anger came back and he returned to normal.
Super Strength: Even by DC standards. He's easily one of the single most physically powerful beings in the entire DCU.
Token Evil Teammate: Forced to work as a member of the League at one point, alongside J'onn J'onnz no less.
Took a Level in Badass: Originally a mental threat and nothing else, Despero has been repeatedly reborn in the Flame of Pytar, becoming more and more powerful with each incarnation.
The Human Flame
AKA: Michael "Mike" Miller
"Impossible? I'm the Human Flame, Milo. I eat impossible for breakfast and crap out unicorns!"
A low-brow thug with just enough intellect to be dangerous to himself and others, Mike Miller was an absolute nobody, until he built a special flamethrowing suit in order to ward off the police and the Martian Manhunter. Incarcerated, he was eventually freed by Libra, who transformed him into a cyborg. Playing a pivotal role in the "death" of the Martian Manhunter, Miller had himself augmented again and again to try and ward of the JLA, eventually becoming a radioactive mass of living fire.
"You knew nothing of me on Mars when I engineered the death of our race under your very nose! You understood nothing of me when I destroyed your new life on this joke of a planet! And you understand nothing of my life as I end yours by ripping you apart muscle by sinew!"
J'onn J'onnz's twin brother in Post-Crisis continuity, Ma'alefa'ak, alias Malefic, is a sociopathic mind rapist and serial murderer turned genocidal madman. Stripped of his psionic powers following his capture, Malefic gained his revenge by engineering H'ronmeer's Curse, a psychic plague that killed almost every Green Martian on the planet. He later followed J'onn to Earth, where he was killed following an assault on the JLA.
Evil Cripple: Given the degree to which Martians depend upon their Psychic Powers, Malefic's loss of them qualifies him for this status.
Torture Technician: Tends to play with his victims for an extended period after capturing them.
"Here we languish, beggars on a hostile world far from our native sun. Forced to grub for survival like insects in the dark—when there are those who live in light, on a world that should be ours...While we huddle on this barren rock, our sacred lands are raped—by those who mock our fate!"
Genetically engineered to be the ultimate Martian warrior, The Marshal of the Red Brotherhood was a powerful political and military figure on Mars II during the Bronze Age. Following Blanx's near destruction of all Martian life, and the encounter with the Thythen, The Marshal, at Bel Juz's urging, launched a coup d'etat against J'onn J'onnz, and then launched an invasion of Earth.
"They are not regular members of my syndicate... and therefore expendable!"
A European mobster who headed up the international syndiacte known as "Vulture", Mr. V was a masked presence who operated through legions of underlings, including one Body Double after another. Confronting J'onn repeatedly throughout the sixties, Mr. V, dubbed "Faceless" by J'onn, was the first enemy the Martian Manhunter truly loathed. He's vanished since the Silver Age, leaving a number of unanswered questions.
The Reveal: During his final appearance, Mr. V is revealed to be Marco Xavier, the supposedly dead Vulture operative whom J'onn J'onnz has been impersonating the entire arc. Whether this was his real identity (Mr. V's suit seems unusually loose on Xavier's skinny frame) and if he really did die in that last confrontation was never confirmed.