Marc Spector is a former professional boxer, Marine, CIA agent, and mercenary. He is currently the vigilante known as Moon Knight, trying to redeem the dark deeds of his past.
Moon Knight first appeared in during the events leading up to the big weapons bust at the Constrictor's weapons auction. He moved his base of operations from Chicago to New York City because a gang he had been trailing went there to partake in the auction. During the bust, Moon Knight met several other vigilantes who he would team up with later, such as Daredevil, Steve Rogers, and Spider-Man.
When Daredevil was dealing with an ex-hand ninja named Kurosame, who had been hired by gangsters to kill Matt Murdock, he called on Moon Knight for back-up just in case any reinforcements for Kurosame arrived. Other gangsters did arrive to try to finish the job after Daredevil defeated Kurosame, but Moon Knight was already there waiting for them and easily incapacitated them.
Moon Knight would team up with Daredevil again when a hit contract was put out on a traveling magic healer who Matt Murdock was about to prosecute in court. Daredevil and Moon Knight fought and defeated the assassin named Omnisight, but while they were transporting him in the Mooncopter to the police station, his partner named Bloodlust flew near them with a jetpack holding a hostage, threatening to kill the person if they did not turn Omnisight over. Moon Kngiht came up with the idea to have Daredevil dress up in Omnisight's costume and then go back with Bloodlust to their hideout, to which Moon Knight would follow. The plan worked, and they were able to arrest Omnisight, Bloodlust, and their associates; however, the woman who hired them escaped.
Omnisight and Bloodlust would not stay in jail for long, though, as they were quickly broken out by the French villain Batroc. Omnisight had used his supervision powers to visually Moon Knight all the way back to his mansion, thus discovering his secret identity as Marc Spector. The three villains then broke into his mansion. Moon Knight had almost finished changing out of his costume when they surprise attacked him in his master bedroom. Despite his valiant effort, the three would have defeated Spector if The Thing had not shown up. Together, the Thing and Spector were able to defeat Omnisight, Bloodlust, and Batroc.
Moon Knight was present during the fight against the Six Fingers of the Right Hand in Central Park. He was unable to overcome the numerical advantage that One-Eyed Jack, Neko, and the Kid had on him, and ended up being taken hostage, only to be saved when the mysterious S.H.I.E.L.D. agent arrived and killed the three of them.