When Spider-Man first traveled to the Negative Zone he befriended a group of rebels battling Blastaar. Their leader was called Dusk, who wore a shadowy suit. The Dusk title had been passed down to the group's greatest warriors to act as a symbol of freedom for their people. However the latest person to take up the mantle had been killed shortly after Spidey's arrival. At the rebels' request, Spidey wore the costume and led the rebels to victory. Spider-Man was allowed to take the suit home with him.
When Spider-Man was accused of murder he donned several different costumes to disguise his identity so that he could continue saving lives. One of the personas that he adopted was Dusk. As Dusk, he pretended to be a mercenary with a quiet and serious personality. He teamed up with Trapster, who had in fact framed him for murder under Norman Osborn's orders by using a duplicate of Spider-Man's webbing to kill a small-time crook called Joey Z. After helping the Trapster escape an attack from the Shocker, Trapster and Dusk became regular allies, taking out some of Osborn's various criminal activities across the city. Although Dusk failed to record a confrontation between Trapster and Osborn where Osborn admitted his role in the murder, he was able to convince the Trapster that the best way to hurt Osborn now was to admit his role in framing Spider-Man for Joey Z's murder. Peter used all four of his new identities to confuse his foes and to contradict speculation that the new heroes were all, in fact, the same person. Once he had cleared his name, he abandoned all of his new personas.
Cassie St. Commons
The golden age hero Black Marvel acquired the four costumes. He then proceeded to give them to four youngsters forming a team that he named Slingers. Lyons provided Cassie St. Commons with the costume and identity of Dusk. She accepted, but had to undertake an "initiation" into the group by making a heroic leap across the rooftop of one building and land on another. While her teammates, Prodigy, Ricochet, and Hornet were all able to make the jump, she did not. When the others were distracted, Cassie did not actually jump, but instead purposefully fell to her death.
But Cassie was reborn, no longer dead, but not truly alive. She was Dusk. She found that she could teleport anywhere in a swirl of shadows, and she had some kind of psychic awareness that enabled her to feel her teammates. When she returned, her fellow Slingers were shocked to see their friend back from the dead.
The Dusk Suit allows the user to become virtually invisible in the shadows and glide short distances. After Cassie St. Common's death, the suit altered using Darkforce energy, allowing her to teleport herself or others anywhere she wished to be. She could manipulate shadows to form objects or constructs of solid dark energy, a power she used to great effectiveness during the battle against Mephisto's horde of demons. She also can regenerate damaged tissue and she has a clairvoyant ability to sense the whereabouts of her teammates, and know if they are in danger, no matter how far away she is from them.