One night Phil Forrest and his partner Danny Stone were hunting The 100, a crime syndicate with 100 members. Sgt. Forrest and Stone became involved in a gunfight with a gang associated with The 100. After Stone was wounded, Sgt. Forrest pursued the fleeing crooks on his own. He ended up at the waterfront, where he ran his car into their car. The 100 had offered the hoods a bounty for the head of Sgt. Forrest, so after another fire fight the hoods killed Sgt. Forrest and dumped his car and body into the river.
Rose Forrest and Danny Stone found the car containing her father's body as it was being pulled from the river. Forrest was severely traumatized and was taken to the hospital. She developed a split personality as a result of her obsession with avenging her father's death. Though incapable of violent action as Rose Forrest, she would fall asleep and sleepwalk in a new and vengeful personality.
After her release from the hospital, Forrest returned to the home she and her father had shared. One night whilst sleepwalking, she rediscovered a secret door that she had found years ago as a child, and entered an abandoned costume shop. There she found a green costume and weapons created years ago by a costumer named Albert Talbot as part of his aborted scheme to turn a woman he knew into a costumed criminal. Donning an auburn wig and taking the costume and weapons, Rose became the Thorn, whose primary motivation was to avenge her father.
When her father's corpse was stolen by members of the Nazi Party, Thorn worked along with Batman to find those responsible and although, the criminals paid for their crime, Thorn couldn't recover her father's body.
- Hand-to-Hand Combat (Basic): Thorn is a skilled fighter.
- Weaponry: Thorn also uses a variety of dangerous weapons.
- Multiple Personalities: To date, Rose has shown four different personalities.
- Barbed Whip
- Shoulder Belt with pouches (a bandolier) that held:
- Thorn-shaped weapons
- Smoke Bombs
- Magnesium Flares
- This version of Thorn, including all history and corresponding appearances, was erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. Even though versions of the character may have since appeared, this information does not apply to those versions.
- 29 Appearances of Rose Forrest (Earth-One)
- 5 Images featuring Rose Forrest (Earth-One)
- 2 Quotations by or about Rose Forrest (Earth-One)
- Character Gallery: Rose Forrest (Earth-One)