Manhunter is a masked vigilante who lives on the parallel world known as Earth-9. Next to nothing is known about this hero's background, not even her true face or secret identity. She began her career within a year of the emergence of Atom. Partnered with a cybernetic canine named Pooch, the Manhunter operated out of post-war Czechoslovakia, hunting down escaped war criminals and bringing them to justice. One of the Manhunter's more notorious targets, was the brutal regime leader, Darkside. Years ago, Manhunter tracked Darkside's trail to an apartment complex in New Atlantis. Finding her inside, she executed her for crimes against humanity. However, the Manhunter soon discovered that the woman she murdered was actually Darkside's twin sister. Consumed by guilt over her misdeed, the Manhunter swore to avenge the woman's death, by executing the real Darkside. The spirit of the dead woman rose from her body, and accompanied Manhunter back to Czechoslovakia. Together, they faced off against Darkside. The Manhunter used a mystical green, Chinese lantern to destroy Darkside's mystical orb of power. With the orb destroyed, Darkside's waning power levels turned against her, destroying her in the process. Darkside's sister was grateful that the Manhunter helped her to find peace.
About ten years ago, Manhunter joined Plastic Man, Joker, Flash, Atom III and the Spectre to form a team called the Justice Society. However, when Superman took over the world, the team opposed him. In their one recorded encounter, Plastic Man and Joker were killed, and Atom was presumably apprehended.
Recently, Manhunter (accompanied by Pooch) and the Spectre broke into the Global Security Centre, north of New Atlantis, in the hopes of rescuing Atom III.
She was recently killed by Powergirl when she was found out to be openly opposing Dent's control of Earth-9 along with various heroes of New Earth.