He along with Judge Mortis are the only ones among the dark judges to lack a helmet of any kind.
He, unlike other Dark Judges uses a weapon as the main way to kill his victims: a flame-spewing trident. This makes Fire the most dangerous of all the Dark Judges as he is the only one with a long-distance attack.
Like his brothers, he is a ghost possessing a transformed corpse.
As a human, Fire was a Judge appropriately named Fuego (Spanish for "fire"). As one of Judge Death's acolytes, he earned the name "Judge Fire" after he burned down a school with the students inside for violating noise regulations.  While still human, he infiltrated a resistance group. Eventually he led this group to sacrifice at the hands of the newly-created Judge Death. 
Once he was transformed into his undead form, he helped murder the entirety of Deadworld. He convinced a woman he had an infatuation with to join them as Sister Despair. After the great massacre, he learned she was keeping the last humans under the ocean for "experiments" and attacked in order to bring 'justice', and to 'possess' her in some form by killing herself. After she died rather than let him take her, he spent years staring at her skull and remembering the event.
Unlike Judge Death, he decided to remain in Deadworld rather than move to other realities.
Having sensed Death's peril after he was trapped in the body of Psi-Judge Anderson, Fire, along with Fear and Mortis crossed the dimension warp to rescue him. Once Death is released from imprisonment and gains a new body, Fire and the other three Dark Judges continued their 'judgement' upon Mega-City One and claimed thousands of victims. Dredd and Anderson intervened, pursued the Dark Judges back to Deadworld, and Anderson channelled the spirits of the Dark Judges' millions of victims flowed through Anderson and seemingly extinguished their spirits forever.
His spirit survived and, with the other Dark Judges, he returned twice more to menace Mega-City One. After the Necropolis massacre, Fire was left trapped in special containment and would remain that way until he was moved to another prison - the Joker intercepted it and freed him, and Fire massacred hundreds of hedonists until he was stopped by Dredd and Batman.
It wouldn't be until 2134 when Fire would rampage again: deliberately released by a Sov agent. His body was swiftly destroyed and his spirit form captured by PJ Maybe.
In 2137, Judge Death freed his brothers and they slaughtered the 4000 strong crew of the starship Mayflower.
Judge Fire appeared in the Dredd Vs. Death video game (and novelisation). He attacks the Smokatorium with the help of zombies. Dredd is unable to fight Fire directly and has to turn on the sprinkler system to force him towards ventilation fans, which shred Fire.
Greg Staples has said Fire was the most irritating Dark Judge to paint. "I hope to never have to draw Judge Fire again in my life. Having to paint fire. Moving fire. Constantly. And things setting on fire? It'll be like my Spielberg "Jaws" moment. I'll just wake up in the middle of the night in a stone cold sweat."