Cassie St. Commons, the "poor little rich Goth," came to New York from Connecticut to study at Empire State University. Although she developed a crush on her new friend Johnny Gallo, it left the feelings of another friend, Eddie McDonough, unrequited. Cassie and her friends were approached by the legendary superhero, the Black Marvel, to join a team he was putting together, and she was given the identity of Dusk, which had formerly been created by Spider-Man to investigate fraudulent crimes against him. Eddie and Johnny also joined the team as Hornet and Ricochet, and they were later joined by a fourth member, Prodigy (Ritchie Gilmore), to create the Slingers. Unfortunately, tragedy was quick to strike the fledgling group -- on the team's first night out in the city, testing their powers, Cassie fell from a rooftop and died.
Cassie's body was discovered by the police the following morning and committed to the morgue. As her body lied there, it began to heal until, in the dead of night, she awoke, amnesiac, and fled. Struggling to remember who she was, Cassie observed Ricochet, Hornet and Prodigy avert a train collision. As Dusk, she saved the life of a young boy whose curiosity over the contents of the wreckage proved dangerous. But she fled before fully reuniting with her friends.
Cassie returned to her parent's home, a kernel of memory nagging at her. She then departed, teleporting to the construction site of the Grand Royale Hotel, where she rescued Hornet, who had been buried alive in a cave-in of the tunnels below. She appeared in his apartment in the evening, before vanishing once more. On the hotel's opening night, Dusk rescued Ricochet after Prodigy hurled him from the building after a fight. Suddenly, the hotel was wracked with explosions, triggered by the Black Marvel. Years ago, he had failed to save innocents from a fire in the hotel, and now, he wanted to give himself the chance to be a hero once again. The Slingers confronted their creator, and then set about rescuing those trapped in the hotel, before it collapsed on Prodigy.
It was later revealed that the Black Marvel's renewed vitality was a result of a deal he had made with the demon Mephisto -- the chance to be a hero again in exchange for his soul. When Mephisto came to collect, he also wished to see what had come of the deal and brought to life the billboard that the Slingers used as their meeting place, using the animated constructs to draw the Slingers into his realm. There, Mephisto subjected the individual members of the group to challenges that embodied their greatest fears and found them wanting. Then, desiring to see how they functioned as a team, pitted them against a horde of his demon minions.
Cassie's powers underwent another sudden evolution, as she transformed into a reptilian form and kept the horde at bay. Impressed by this display, Mephisto offered a choice - return home and leave the Black Marvel's soul or risk all to save him. Gallo attempted to shatter the crystal holding the soul with one of his discs but failed. He then cast off his costume, confronting Mephisto not as Ricochet but as Johnny Gallo. Mephisto allowed him to spare one soul, but then attempted to trick him with an image of his mother. Prodigy prevented him from falling for the deception, and the others followed his lead, renouncing their costumed identities. Mephisto freed the Black Marvel's soul, and the Slingers were returned to Earth.
Cassie elected to depart the group, hoping to learn more about herself and what she had become. (It had been revealed that the origins of the Dusk guise lurked somewhere in the Negative Zone, where it was the identity of a native superhero there). Although he had been passingly seen with the group since then, her ultimate fate remains unknown now that the Slingers had drifted apart.
Sometime after the superhuman Civil War Dusk was kidnapped by Puppet Master along with other female heroes like Tigra, Silverclaw, Stature, and Araña and was transported to Puppet Master's new villa in Chile. Ms. Marvel who was investigating why Chilean army tried to free Exterminatrix stumbled on Puppet Master's clay mine, that he had been using to collect special clay, that let him control more minds than ever before. Ms. Marvel managed to stop him but not before he blew up the house and himself along with it. Dusk escaped with the other heroes just before the villa exploded.