Long ago, the Planet Mars was home to a supremely powerful malignant race simply known as the Burning. These beings
had vast pyrokinetic abilities, reproduced asexually, and made extensive plans of intergalactic conquest.
Fearing that these beings would ruin untold lives and species, the Guardians of the Universe intervened and defeated the evil race. In order to make sure that the Martians never again rediscover their burning origins, the Guardians split them into two distinct races and instilled both of them with a deep weakness and fear of fire. Thus the two Martian races were born: The White Martians, and the Green Martians.
Over the following millennia, the Green and White Martians evolved and developed next to each other. The Green Martians developed into a peaceful civilization of philosophers, while the White Martians became savage war-mongers. The two races squabbled constantly. Both races called their home planet Ma'aleca'andra.
Somewhere in that period, the two races created clones of themselves to serve as workers on the planet Saturn. The clones of the Green Martians became Red Saturnians, while clones of the White Martians became White Saturnians. While the Green Martians treated their clones as equals, the White Martians treated their clones as slaves. So big was this rift that eventually it led to a civil war. The atrocities committed by the White Martians were so great that they forced the Green Martians to imprison their entire race in the Still Zone (possibly the same as the Phantom Zone). In the aftermath of the war, both races of Saturnians were given their freedom, and the Green Martians were left to reign supreme over Mars.
The Green Martian civilization thrived for hundreds of years to come after the war. They explored space and other planets, even visiting Earth and inspiring the Egyptians to build their massive pyramids. It was a prosperous time for them.
The story of their fall would begin with the birth of two twin brothers: J'onn J'onzz and Ma'alefa'ak.
Both brothers grew up to be Manhunters (Policemen), but Ma'alefa'ak was a sociopath, and soon found himself committing the most heinous crime in the Martian society: Mind rape. For this transgression, the Martian assembly removed his telepathic abilities, an act he did not understand and the source of his hatred towards his race. Now basically a cripple and branded a freak by others, Ma'alefa'ak turned to thoughts of vengeance. He soon created a deliverer of his wrath: a telepathic plague he called "Hronmeer's curse," after the Martian God of death and art. A plague which, as the only non telepathic Martian, only Ma'alefa'ak would survive.
Like fire, the plague sweeped across Mars, killing every Martian it came in contact with. And being immune, Ma'alefa'ak was enjoying the fruits of his labor, until finding out of another Martian who survived the plague: his brother, J'onn.
The brothers fought, and in the aftermath Ma'alefa'ak was supposedly killed, and J'onn was left as the last surviving Martian.
It is unknown for how long J'onn j'onzz wandered the dead planet, losing his mind, until the human scientist Doctor Erdel unwittingly transported him to Earth. There J'onn J'onzz adopted our world as his own and became the Martian Manhunter, eventually coming to serve with other heroes as an invaluable member of the Justice League.
In the Prelude of Darkseid's attack on Earth, Martian Manhunter was killed by Darkseid's herald, Libra. But before he passed away, he sent out one last telepathic burst to several people he considered friends: Batman, Superman, Black Canary, Green Lantern and Gypsy. Their unconscious minds used this imprint to write a book about his life, and about his race, allowing that the history of the Martians was never forgotten.
J'onn J'onzz was buried on Mars.