The Intelligencia was formed by the Leader. He recruited some of the greatest criminal minds on Earth for one purpose: recollect the lost information of the Library of Alexandria. He first got the Wizard to join, followed by Egghead, the Mad Thinker and the Red Ghost. In order to safeguard the information, they got the cooperation of Doctor Doom. Together they created a device that made them fall slightly out of time with the real world, making them undetectable to even the greatest of technologies. The device was powered by their combined mental capabilities (Doctor Doom excluded). Their first heist was a success, stealing one third of the information from the Eternals.
Over the years the team continued to plan for their future heist while at the same time endeavoring on solo missions. They often assisted each other in prison breaks, all the while keeping their alliances secret. They were also responsible for resurrecting and reforming the Absorbing Man, Sandman and Klaw on multiple occasions in order to keep them unaffiliated with one another. When Egghead was killed, they needed a replacement to make their machine work. The Leader chose MODOK. They stole the next piece of information from Wakanda, a remarkable feat considering the nations advanced technology. With this information, Doom built a tachyon beam that inadvertently caught the attention of the being known as the Beyonder. After these events, the team did smaller missions to obtain further information.
The final piece of information was located in the Library of Atlantis, the team luckily retrieving it before it's destruction. Upon return to Latveria with the info, they were betrayed by Doom, who stole it all. The team disbanded after the Leader left the battle with Doom, knowing they could not hope to beat Doom in his own land.
Years later, the Leader was approached by MODOK, who had some interesting information. With info he had learned from the texts, MODOK used gamma and cosmic radiation to create the Red Hulk, who could be used to stop the Hulk. They also needed to take out the opposition, which was the eight greatest minds on Earth besides their own. This also included revenge on Doom. With MODOK's technology, the Leader also created the Red She-Hulk. The Red Hulk drew up a battle plan for the Intelligencia, but was cast out of the group. Now seemingly allied with Lyra and Doc Samson, the Intelligencia made their first move. They successfully capture Reed Richards and Doctor Doom. Their next possible targets are Hank Pym and Hank McCoy.
The Red Ghost and the Super-Apes
The Mad Thinker
The Frightful Four