The Martian Manhunter (J'onn J'onzz), is a comic book superhero appearing in DC Comics. He is a native of the planet Mars (or Ma'aleca'andra, as it was known in his native tongue; this is similar to Malacandra, the name used by the inhabitants of Mars in C.S. Lewis's Out of the Silent Planet) and possesses powers beyond those of normal human beings, including telepathy and the ability to change shape. His usual appearance is of a tall, hairless, green-skinned humanoid. He is highly sensitive to fire; in some stories this weakness is a physical weakness, and in others it is psychological. He has an odd addiction to Oreo cookies; this was later changed to 'Chocos' (presumably due to licensing problems). A recent story in the JLA comic book indicates that the Guardians of the Universe instilled the aversion to fire into the Martians to prevent them from overrunning the universe. This weakness has been addressed in recent times.
J'onn J'onzz first appeared in 1955, in a back-up story in Detective Comics #225 written by Joseph Samachson and illustrated by Joe Certa. In the story, J'onn J'onzz was accidentally teleported to Earth by a human scientist, Dr. Erdel, who immediately had a heart attack and died, leaving the Martian stranded and unable to return through the so-called "Erdel Gate" through which he had been teleported. Fortunately, he was able to use his powers to fit in; adopting a human-like appearance and calling himself "John Jones", he joined the police force, secretly using his alien powers to help the inhabitants of his new home planet.
Later, during the revival in superheroes that became known as the Silver Age of Comic Books, the Manhunter from Mars adopted a more characteristically superheroic modus operandi, openly fighting crime in his real green-skinned form.
Later comics have revealed that Mars was dead when J'onn was taken, killed by a mental plague deliberately started by his brother Ma'alefa'ak. It has also been stated that, prior to becoming a superhero in his real form, he took the identity of the Bronze Wraith, and fought crime with the Justice Experience (a group that essentially existed to fill the gap in post-Crisis continuity where the Silver Age should be).
The history of the Martian Manhunter is closely linked with that of the Justice League - he was a founding member of the superhero team in the 1960s, and his appearances with the League kept him in the public eye long after his own series (which ran as a back-up in Detective Comics and later in House of Mystery) was cancelled. During the Justice League International series, J'onn was shown to be obsessed with Oreos, thanks in no small part to the influence of Captain Marvel; the story of how he got over this addiction was later told in his series (which, in a retcon, referred to them as "Chocos").
It was also in Justice League International that it was revealed that his familiar appearance was not his true Martian form, but a "compromise" form between his true self (described by Hawkman as "like... like Gumby!") and a human appearance. This concept would be refined in his own series, which would explain his real form was private and that, even on Mars, his "public" appearance was the familiar version.
In addition to serving in the League under his own identity, he also joined (under duress) under the alias of "Bloodwynd".
The Martian Manhunter received his own ongoing series in 2000. Written by John Ostrander, and illustrated by Tom Mandrake (with fill in art provided by Bryan Hitch, among others), it lasted 36 issues before being cancelled due to low sales. Outside of this, the Manhunter appears predominantly in the Justice League comic book. He is, famously, the only character to be involved with every "incarnation" of the League. (From the late 1960s to the late 1970s, J'onn was absent from the JLA and, indeed, from the DC Universe entirely, having left to find New Mars. This entire storyline was retconned out during the Crisis, and it is now assumed he was with the team at this time.)
Also, he has had a few short appearances in the Sandman comic, in the album Preludes and Nocturnes, in which Morpheus, the dreamlord, inquired him about the whereabouts of his Dreamstone. He also appeared in the final volume of Sandman, The Wake, having a conversation with Batman and Clark Kent.
In Grant Morrison's JLA, and his own 2000 series, it was established that the Martian Manhunter was the most recognized hero in the Southern Hemisphere, and that he maintained a number of different secret identities, many of them outside the United States. However following two incidents in which John Jones separated from the Martian Manhunter, he has decided to focus on his original human identity and retire the others.
In an attempt to conquer his fear of flames, the Martian Manhunter made a deal with a flame-wielding villainess named Scorch, who wanted his telepathic help dealing with her own mental issues. This story revealed that 20,000 years ago, there was an extremely dangerous race of beings called 'The Burning', which caused large fires to help themselves asexually reproduce. The Guardians of the Universe split these creatures into the Green Martians and the White Martians, changed their reproductive behavior, and gave them an inherent fear of fire in order to stop their species from destroying much of the universe. When the Martian Manhunter confronted his fear of fire, he reverted into one of these ancient creatures, and changed his name to Fernus. His genetic memory pools then identified threats, such as Vandal Savage who killed one of The Burning on ancient Earth. This same genetic memory made him hate the Green Lantern, due to his association with the Oans.
Fernus' powers were increased over J'onn's as well; for example, he could phase other beings rather than just himself, allowing him a new way to kill someone. This possibly implied that he could also shape-shift other people, too. He has access to either pyrokinesis or metamorphic powers, that kept him aflame (even during space travel). He could breathe fire of such intensity it could harm Scorch (who had previously been thought immune to damage through fire). His strength allowed him to dominate the Justice League in combat even without his mental attacks. He also could heal himself from almost total destruction within seconds. In short, Fernus was a much more powerful version of the most powerful being on Earth.
Although Superman conceded that the Martian Manhunter is the most powerful being on the planet, the Justice League eventually defeated Fernus by re-enlisting Plastic Man, who is immune to the psychic powers of the Martian Manhunter, and has superior shape-changing abilities. The story also hints that this is the reason that Plastic Man was originally brought to the Justice League by Batman, who wanted a balance in place in case the Martian Manhunter ever got out of control.
By the story's end, J'onn himself the being Fernus asexually reproduced, due to help and encouragement on the astral plane by Manitou Raven, The Atom, and Major Disaster. After destroying Fernus (but hinting that Fernus was not destroyed) J'Onn grieved the passing of Scorch, who's relation had arguably become a type of love. Later J'Onn would explain to Superman that his aversion to fire had changed: he was now invulnerable to flames unless they were flames of passion (fans debate on whether this would include a pyrokinetic being with powers effected by emotions or even a simple arsonist who starts fires because of an insane reason).
Though J'onn was thought killed in the recent explosion of the Justice League Watchtower, JLE member Manitou Dawn received a telepathic vision of J'onn assuring her that he will reveal himself, in time but needed her help to keep an eye on a mysterious, newly-powerful telepath - the mind-controlling villain Key - whose abilities he had always managed to dampen before. Manitou Dawn has subsequently tried to contact J'onn in the astral plane, without success. J'onn has since resurfaced (in Infinite Crisis), unconscious and hooked up to a strange building, reminiscent of the vibrational forks from Crisis on Infinite Earths (with the Anti-Monitor's corpse attached to it), along with Lady Quark, The Ray, Black Adam and Breach. Apparently, Superboy Prime took J'onn with him before he blew the Watchtower apart, and somehow J'onn had managed to maintain enough telepathic consciousness to warn Manitou Dawn.
Golden Age Manhunter from Mars
In 1953, a green-skinned manhunter from Mars named Roh Kar arrived on Earth and captured an escaped martian convict with the assistance of that era's Batman. This version had devices that allowed him to disappear and teleport, it is unknown if he had any additional abilities aside from superior Martian physiology.
J'onn J'onzz (he was never referred to as the Martian Manhunter, or even as a Martian) appeared in the 1994 live action made-for-TV movie Justice League of America. He appeared to find shapeshifting difficult, and no mention was made of any other powers. He was played by David Ogden Stiers.
In the Justice League animated series, J'onns's history is even more closely tied with that of the League. He would not be referred to as the Martian Manhunter until the series was recreated as Justice League Unlimited, and is always listed as "J'onn J'onzz" in the show's closing credits.
In the series, the Justice League originates as a temporary uniting of Earth's heroes against an alien invasion; the invaders had previously invaded Mars, wiping out all the inhabitants except J'onn J'onzz, who travels to Earth to warn of the invaders, and joins the fight against them. When the invaders are defeated, he chooses to remain on Earth as a member of the League. His original Martian form is loosely similar to his well-known form, but his skin is scaly, his head and some of his extremities end in sharp points, his eyes are further apart, and he has no nose. In the series, he adopts his well-known form when Batman is skeptical to believe an alien he has just met: J'onn responds by transforming into his famous form and suggesting that Batman would be more comfortable with this appearance. Soon after defeating the aliens that destroyed Mars and invaded Earth, J'onn was enlisted as a member of the newly formed Justice League.
During his time with the League, J'onn assisted in finding Morgaine Le Fay only to be countered with images of Mars restored by the witch. Upon sweeping through the mind of the demon, Etrigan, he realized her manipulation and destroyed the Philospher's Stone, which she had been searching for.
After the Watchtower was destroyed when Batman plunged it into the Thanagarian Hyperspace Bypass, the League was reformed to enlist over 50 other members into a new Watchtower where J'onn would monitor all missions. Unfortunately, the two years he had spent up on the Watchtower had caused J'onn to become extremely remote from the peoples of Earth, even to the point (as Wonder Woman points out) of disliking humanity. Once Diana revealed this about J'onn, he decided to resign from active duty in the League to live among Earth's citizens and learn more about them. He is later shown to be with a women in China whom he leaves while he goes off to fight. J'onn J'onzz is voiced by Carl Lumbly.