Galen was born to an incredibly rich family, her father, Garfield DeMarco inducted her into the Academy of Law as a child.
The character was created by John Wagner and Carlos Ezquerra, in 1997, she appears in the 2000AD and Megazine stories of Judge Dredd as well as in her own series, DeMarco PI.
Major Story Arcs
Life as a Judge
DeMarco was first introduced in the Judge Dredd arc known as "The Pit" a story about Judge Dredd being sent to oversee and turn around one of the worst performing Sectors in Mega-City One, a place that had long since become a dumping ground for Judges that had screwed up.
Judge Dredd found DeMarco to be one of the most competent Judges in the Pit, and was curious as to how such a promising Judge had ended up there, so after putting her in charge of rooting out the Sector's corrupt Judges he had another Judge, Judge Castillo investigate her.
Castillo discovered that DeMarco was secretly having sexual relations with another Judge named Warren (an unjudicial liaison). Relationships of any manner are strictly prohibited for Judges as they are perceived to make them emotional and illogical, but being that DeMarco revealed her "crime" by saving Castillo from an unrelated incident, DeMarco was shown leniency, whilst her lover, Warren, was not.
Bitter about the course of events, and on the run from punishment at the hands of Justice Department, Warren kidnapped DeMarco to get money for his escape. After getting the cash there was a struggle, and DeMarco kicked Warren from the hovercar they were traveling in and he fell to his death.
Promotion to Sector Chief
After many successful missions, including a Hotdog Run into the Cursed Earth, and a search and rescue mission to find a kidnapped Judge Dredd, DeMarco was promoted to Sector Chief.
One of DeMarco's first orders was to bring Judge Dredd into her sector, and onto her team. Judge Dredd was unsure about her reasons for doing this, and after a short period it became apparent that DeMarco had actually grown to have feelings for him, she kissed him out of the blue.
After being kissed, Dredd reprimanded DeMarco and left, upset, she left the building and went looking for trouble, finding it and being taken by surprise she was kidnapped.
DeMarco was thrown into a Gladiator pit and forced to fight well-armed opponents, she was stabbed, slashed, and beaten repeatedly, and was close to death when Judge Dredd turned up and rescued her.
After making sure that DeMarco was going to be OK he left the Sector, choosing not to report her previous case of misconduct.
Quitting Justice Department
Information about DeMarco's misconduct eventually reached Dredd's enemy in Justice Department, Judge Edgar, she decided to investigate further, bringing in DeMarco and having her drugged and interrogated, hoping to implicate Dredd in an unjudicial Liaison.
To Edgar's disappointment, DeMarco revealed nothing new under interrogation. As punishment for her earlier misconduct, Edgar bitterly strips DeMarco of her position and orders that she undergo re-education. Refusing these terms DeMarco makes the decision to quit as a Judge.
After a short time DeMarco sets up her own detective agency.