Vidad and five other Cogitors chose to stop all contact with outside world, apparently notwithstanding the obligations that stemmed from their revelations. These six Cogitors were named Ivory Tower Cogitors and lived on Hessra.
Centuries later he reemerged during the Butlerian Jihad. He attempted to broken a peace deal between the League of Nobles and the Thinking Machines. His actions failed and in fact inflamed the two parties' conflict even further, thanks to Iblis Ginjo.
After Serena Butler's death, Vidad spent the following years on Salusa Secundus, studying historical records and recent philosophical treatises. He also meddled in the affairs of the Jihad Council. During his absence Hessra was conquered by the Titans and his fellow Cogitors were killed. Vidad was tended with now ancient Keats, and another secondary, Rodane.
After Vorian Atreides suggested the Great Purge, a massive assault against Omnius, Vidad sought to return to Hessra and consult his fellow Cogitors. On their arrival, the ship was piloted by Rodane when they were intercepted by neo-cymeks and received the last signal of a secondary-cymek who tried to warn them.
Rodane then attempted to escape the planet. Keats grasped the controls and accelerated fiercely to lose their pursuers. The speed was so immense that his elderly body could not withstand the pressure; his bones cracked. When Rodane recovered his senses, he found the old Secondary dead, having given his life to save the ancient Cogitor. Vidad ordered the ship to move to Corrin, once more to meet with Omnius, where he revealed to the evermind both the location of the Titans and the plans of the Great Purge.
Vidad was now the last of the Ivory Tower Cogitors. After the Purge, he returned to Salusa, although he never mentioned his meeting with Omnius. Vidad also helped in some conversation Abulurd Harkonnen to come to the conclusion that the man who murdered the Grand Patriarch Xander Boro-Ginjo was none other than Yorek Thurr, who returned after presumed dead for years.
Vidad remained in the Hall of Parliament when the Cult of Serena attempted a violent march against the city. Vidad with his Secondaries attempted to call them to reason and they were wrong to deify Serena Butler, an ordinary woman whom he had met in person. The Cultist considered it a blasphemy. They accused him for proposing peace with the Thinking Machines and driving Serena to her death and compared them to a cymek.
The crowd approached and his Secondaries fled inside the building. The Cultists shoved his pedestal and made the preservation canister fall down, and then crushed it with pipes and makeshift clubs.