Jubilation Lee's parents were killed by metamutant-hunting Sentinel robots, forcing the young metamutant to hide in New Gotham's largest shopping mall. In the deep sub-basement caverns of the shopping mall, Jubilation tripped across a trap set for Dark Claw, who was ambushed, wounded, and facing the possibility of death if he could not get away from his pursuers. Although Dark Claw eventually escaped, he was in rough shape, and Jubilation's metamutant light show helped him to get away safely.
Impressed by her attitude and abilities, Logan Wayne took the young girl under his wing. Jubilation wanted to adopt the alias "Death Urge Overdrive," but Dark Claw insisted that she instead take the name "Sparrow." Although Sparrow thought her powers were the solution to every problem, Dark Claw worked hard to get her to rely on her brain, information resources, and strategic planning first, actually placing herself in physical danger only as a last resort.
The New Gotham madman known as Hyena delivered a clue to Dark Claw tipping him off to where he was going to strike next: "Black and white and red all over." Dark Claw immediately deduced that Hyena's clue pointed to the Gotham Gazette Printing Plant and headed toward the plant with Sparrow in the Claw Copter, suspecting that Hyena was going to detonate a bomb there.
Sparrow piloted the Claw Copter outside the Gotham Gazette Printing Plant as Dark Claw confronted Hyena within the building. As Dark Claw traded blows with Hyena, Sparrow monitored Dark Claw's life-function readings and kept in contact with Dark Claw via a communication link. Dark Claw noticed that Hyena was wearing a static electricity discharge wire on his wrist, suggesting that Hyena's plan was to go inside the guts of the typography computer rather than plant a bomb. As the battle between Dark Claw and Hyena spilled out onto the roof of the printing plant, Sparrow provided cover from the safety of the Claw Copter. But when the Pack, Hyena's gang of street thugs, began shooting at Dark Claw from an adjacent building, Sparrow flew by with the Claw Copter so that Dark Claw could hop aboard. The overly aggressive Sparrow prepared to turn around for a strafing run, but Dark Claw grabbed hold of the controls just in time to pilot the Claw Copter away from the Pack's heat-seeking missiles, nearly colliding with the S.H.I.E.L.D. Helicarrier in the process.
Returning to Dark Claw's underground Barrow, Sparrow landed the Claw Copter in the roof hangar and began hacking into the Gotham Gazette typesetting computer as Dark Claw ascended to his penthouse suite. Sometime later, Dark Claw returned to the Barrow along with the former government operative known as the Huntress, who had recently uncovered Dark Claw's secret identity while snooping around Logan Wayne's penthouse. Sparrow vehemently voiced her disapproval of Huntress' presence in the Barrow, but Dark Claw explained to his sidekick that he could not simply take Huntress "out in the woods and loose her."
Sparrow's anger subsided as she showed Dark Claw that she successfully hacked into the Gotham Gazette typesetting computer. Accessing the headlines that Hyena altered for the next day's newspaper, Sparrow, Dark Claw, and Huntress concluded that Hyena was planning to poison the President of the United States with sodium-cyanide when Air Force 1 departed from Gotham International Airport in twenty minutes.
Twenty minutes later, Sparrow, Dark Claw, and Huntress were aboard the Claw Copter and hovering over the Gotham International Airport. As Sparrow piloted the Claw Copter alongside Air Force 1 and matched its speed, Huntress used her crossbow to secure a grappling hook on Air Force 1's landing gear. Dark Claw then used the grappling hook to board Air Force 1, and eventually saved the President from Hyena's evil scheme, although Hyena managed to evade capture once again.
At some later point, Sparrow pulled the Clawmobile up behind 'Lenny's Bar and Grill, where Dark Claw had just been attacked by a pair of cyber-ninja assassins while playing poker in his undercover guise of "Patch Malone." Since the assassins recognized him out of costume, Dark Claw realized that Lady Talia was back in town. Sparrow and Dark Claw returned to the Barrow, where Sparrow accused Dark Claw of "falling to pieces" whenever Lady Talia was around. Sparrow wanted to go after Lady Talia and noted that it was uncharacteristic of Dark Claw to hide in the Barrow, but Dark Claw said that he had to instead train in the Danger Cave because he needed to be at his beast when facing Talia. Sparrow reluctantly obeyed and sat up in the Danger Cave control room as Dark Claw ripped apart life-model-decoy robots patterned after his deadliest foes.
Suddenly, the lights went off and Sparrow was ambushed by Lady Talia, who bound and gagged the teenager. With Sparrow out of action, Lady Talia attacked Dark Claw in the Barrow as a helpless Sparrow watched. After a fierce battle, Lady Talia impaled Dark Claw through his chest with her cybernetic claw. With Dark Claw seemingly dead, Sparrow's eyes filled with tears as Lady Talia approached her. As Lady Talia used her claw to free the young metamutant from her gag, the tearful Sparrow asked Talia if she was going to kill her as well. But Lady Talia responded that she would not kill Sparrow because she was an innocent. Lady Talia, who now regretted killing her beloved Dark Claw, was about to take her own life when Dark Claw spoke. Although severely wounded, Dark Claw's metamutant healing factor prevented him from dying. As Dark Claw and Lady Talia made peace with each other, an impatient Sparrow asked if someone could untie her.
Sparrow has an extensive training in martial arts, forensics, criminology, acrobatics, stealth, disguise, and escapology.
Her naturally high intellect allows her to excel in computer science and more importantly as a skilled detective. Sparrow has a firm grasp of assorted scientific techniques including biology, engineering and genetics. She is also a brilliant and experienced strategist with impressive leadership skills.
Sparrow has the metamutant power to generate bright bursts of energy plasmoids from her fingertips. The globules obey her mental control, traveling where she directs them, arranging themselves in balls, streamers, and other shapes, and exploding when she wishes. The strength of the energy can range from a multitude of colorful sparkles capable of temporarily blinding a person to a powerful detonation capable of smashing objects and destroying property, or a precision burst inside a human's brain simulating the effects of a massive stroke. Sparrow can absorb the fireworks back into her own body without harm.