When a top-secret program attempted to recreate the original Weapon X experiment that involved the feral mutant Wolverine, they failed to secure a test subject who could survive the bonding process of the virtually unbreakable metal Adamantium to their skeleton. Seeking to take the project in a new direction, the project's director, Doctor Marin Sutter, recruited renowned mutant geneticist Doctor Sarah Kinney and tasked her with creating a clone.
Using the only available genetic sample from Weapon X, which was damaged, they were unable to salvage the Y chromosome after twenty-two attempts. Kinney proposed they create a female clone, and though her request was initially denied, she still went ahead and produced a viable female subject, prompting Sutter to reconsider. Despite resistance from his protégé Doctor Zander Rice, whom Sutter had raised after Rice's father had been killed by a bestial Wolverine at the original Weapon X Project, Sutter allowed Kinney to proceed. As revenge for her insubordination, Rice forced Kinney to act as the surrogate mother for the clone, and she gave birth to "X-23."
Raised in captivity, X-23 was trained to be a weapon. Kinney did her best to ensure the child retained some semblance of humanity, but her efforts appeared to be in vain. After seven years, Rice had X-23 subjected to radiation poisoning in order to accelerate the activation of her mutant gene, and forcibly extracted her claws and coated them with Adamantium. Next, Rice created a chemical compound he called "trigger scent" that sent X-23 into an involuntary berserker rage upon smelling its presence. This "trigger scent" was tested on X-23's master, one of few people who treated her with kindness. X-23 was forced to kill her master in berserker rage. Three years later, X-23 was sent on her first field mission to kill Presidential candidate Greg Johnson. She was assigned the mission as somewhat of an "advertising" ploy. Numerous other missions followed, as X-23's services were sold to the highest bidder. She was left emotionally stunted as a result. Her missions took her to locations all over the world, including Saudi Arabia, Las Vegas, Japan, Colombia, the Congo, and many others. For one mission she was assigned to pose as the Kingpin's daughter and kill the ones who had captured her, bringing the head of their leader back. Rice, in an attempt to avenge his father's murder, abandoned X-23 on a particularly dangerous mission, but she survived against overwhelming odds and managed to return to the facility. Although she was punished for not coming back with Rice.
Sarah Kinney let her out once, not as an attempt to escape but instead to use X-23 to help her find Kinney's niece, Megan, who has been kidnapped. X-23 found and rescued her with ease. Ultimately, Rice persuaded Sutter to hand control of the program over to him, then secretly ordered X-23 to kill Sutter and his family. X-23 was able to kill Sutter and his wife but was unable to kill their son. Instead, she let him live. Later, Rice revealed to Kinney a chamber with dozens of incubation pods containing female clones before he fired her. Before fleeing the facility with X-23, Kinney gave her one last mission - destroy the pods and kill Rice. However, Rice was able to exact revenge on Kinney from beyond the grave, as he had earlier exposed her to the trigger scent, sending X-23 into a rage that caused her to kill her mother. As she lay dying, Kinney named X-23 "Laura".
X-23 traveled to San Francisco and tracked down Megan and Debbie (her mother's sister). Introducing herself as Sarah's daughter, she moved in with them. Although Megan experienced vivid nightmares of her abduction, her family believed these to be utter fantasies. X-23 informed Megan that the man in her nightmares was indeed real and that she had killed him.
Debbie's boyfriend turned out to be an agent for the Facility who had been instructed to manipulate X-23 into killing Megan and Debbie using the trigger scent. However, the agent fumbled the assignment and was killed by X-23. Facility agents stormed the house. X-23 managed to get Megan and Debbie to safety by triggering an explosion in the house, buying some time. After X-23 and Megan parted, X-23 decided to confront the man who made her creation possible -- Wolverine.
X-23 tracked Wolverine to Xavier's mansion and engaged him in a battle, defeating him via tactics and maneuverability. However, she did not kill him. Instead, she told him why she had come. Wolverine revealed that he was aware of X-23's ordeal, having received a detailed letter from her mother. The talk was interrupted when Captain America came to arrest Laura.
As a captive of S.H.I.E.L.D. Laura was interrogated by Captain America and Matt Murdock. Despite the mayhem in her past, Matt Murdock accepted X-23's innocence. Captain America wanted X-23 to atone for the murders she had committed. However, he ultimately freed X-23 in order to avoid S.H.I.E.L.D.'s exploitation of her as their own weapon.
X-23 surfaced in New York two years later and was found living on the streets by a pimp named Zebra Daddy, who took her in and employed her as a prostitute. X-23 met Kidon Nixon, a young mutant with the ability to freeze time when in danger. Together with Kiden's teacher, they rescued another young mutant, the feral Catiana, from an angry mob. Zebra Daddy tracked X-23 down, but with the aid of her newfound friends and the mutant named Felon, Zebra Daddy's thugs were defeated. X-23 killed him to save the lives of her friends.
She later returned to help the X-Men save victims of a car accident, after which she was enrolled at the X-Men's Xavier Institute.
X-23 quickly became very protective of Wolverine, attacking his teammate Bishop after he felled Wolverine during a training session. She also took to observing Wolverine on the mansion's security monitors but was away on a mission during ordeal in hell. When she returned to find them gone, she waited, and waited, and waited...as they didn't return she struck out on her own, doing what she'd been made for, but under her own rules, as she set about killing those that she was paid for and surviving in the world that was falling apart until the x-students returned.
