In pop culture, the New World Order (or nWo) is most commonly associated with the group of wrestlers that debuted as a group within the WCW in the mid-90s. However, Marvel introduced its own version of the New World Order in 1993 that continued until 1997, a mere year after the WCW's iteration came into existence. And in the same way that the WCW recruited some of the biggest wrestlers of its day, Marvel's NWO included heavyweights like the Hulk and Juggernaut.
Led by Hulk "Hollywood" Hogan, one of the most popular professional wrestlers in the world, the nWo gained massive popularity within the world of wrestling. The storyline of the former "good guy" Hogan turning bad and attempting a hostile takeover of the wrestling world brought massive returns in viewership and was instrumental in the rivalry between the WWF and the WCW as the most popular wrestling organization of the era.
Although the wrestling world's version of the New World Order was the most popular, it was by no means the most sinister version. That designation goes to Marvel's version of the organization, who was initially led by the Red Skull.
Marvel's version of the NWO came into existence when the Red Skull purchased an area of land in the Amazon and recruited several villains to assist him in his bid for world conquest in The Incredible Hulk #403, by Peter David and Gary Frank. This attracted the attention of the Pantheon, who counted the Hulk among their membership at the time, and the Green Goliath was sent to investigate.
Upon arriving in South America, Hulk was ambushed by the Juggernaut and taken captive by the NWO. During this time, the NWO achieved perhaps their greatest victory by using team member Mentallo to brainwash the Hulk and manipulate him into fighting the Avengers. The victory was short-lived, however, as the Hulk broke free of Mentallo's mind control and simultaneously knocked out both Juggernaut and the majority of the Avengers with the psychic backlash.
Unknown to either Hulk or the Avengers, a government agent was sent to investigate the area before any of the heroes had arrived. The agent was captured by the Red Skull and experimented on in an effort to create a being who could assimilate the powers of all of the NWO members into one body. A creature called Piecemeal was the result of the NWO's experimentation, and managed to escaped the laboratory of the New World Order during the commotion caused by the arrival and subsequent battle between Hulk, Juggernaut, and the Avengers.
After the NWO's defeat at the hands of the Hulk, the Red Skull orchestrated a plane to crash into the headquarters of the New World Order in the depths of the Amazon jungle in order to make it appear as though the operation was destroyed. The NWO moved underground, and as the Red Skull addressed the members of the organization, one of his scientists informed him of Piecemeal's escape. In frustration, Red Skull literally shot the messenger and was not seen again with the organization.
The New World Order was not heard from again until years later when the Hulk was taken by Apocalypse and made into the Horseman of War. Juggernaut was sent to investigate, along with the Absorbing Man, Rick Jones, and Rick's granddaughter from a possible future, Janice. With his already ample powers bolstered by Apocalypse, Hulk was easily able to defeat both Juggernaut and the Absorbing Man, but was snapped back to his senses when he hurt his old friend Rick Jones.
Enraged and disgusted by his actions, the Hulk stripped off his War outfit and leaped away from the scene. Expecting to be handsomely compensated, Juggernaut and the Absorbing Man took the sword the Hulk had wielded as War that was left behind when he fled the scene and presented it to the NWO.
In perhaps their final mistake, the New World Order accepted the sword and brought it into the chambers of their inner council to be examined. While the gathered leaders of the NWO were looking over the sword, Apocalypse appeared to them in a hologram projected by the sword. After thanking them for their unwitting assistance in testing the monitoring capabilities of the weapon, he bid them farewell before remotely detonating the sword, and presumably killing the core leadership of the NWO in the process.
The New World Order has not been seen or heard from since their destruction at the hands of Apocalypse. Although a revival of the organization is not out of the question, it is highly unlikely considering the Red Skull's distancing from the organization he founded, as well as Mentallo joining the X-Men's new society on Krakoa and Juggernaut's position as former X-Man and possible protector of Krakoa in his upcoming series.