When the Celestials Third Host arrive on a mission of cultivation. Ajak formed a special bond to the Celestials, serving as their emissary to others. Zuras and Ajak helped arrange the Celestials' departure, and Ajak placed himself in suspended animation within the City of the Space Gods which the Incas had built for the Celestials to await the return of the Fourth Host to judge the Earth. As the Eternals prepared for the Fourth Host Zuras assigned Ikaris to attune his senses so that he would be able to sense their arrival and revive Ajak to greet them.
When the Fourth Host finally came, Ikaris and Ajak greeted them alongside the human archaeologist Doctor Daniel Damian and his daughter Margo, but the Deviants hoped to turn humanity against the Celestials by tricking them into an attack. The Eternals revealed their existence to humanity for the first time in order to quell the humans' fear of the Celestials and Deviants, and they made close friends of the anthropologist Doctor Samuel Holden. Warlord Kro introduced Thena to the Deviants Karkas and Ransak while she visited Lemuria, and Thena brought them back to Olympia with her to escape the prejudice of their own people. Ajak joined the rest of the Eternals in forming a Uni-Mind to analyze the Fourth Host.
Recently Ajak joined God Squad with Demogorge, Hercules, Snowbird, Mikaboshi and Amadeus Cho to kill Skrull gods Kly'bn and Sl'gur't during the catastrophe dubbed the Secret Invasion of Earth. During their journey through Dreamtime they fought Nightmare and his army of nightmares, but managed to escape. Soon after this a Skrull agent who was impersonating Amadeus Cho's coyote puppy crashed the ship given to them by Altjira and stranded them in the middle of alien pantheons who where now serving Kly'bn. Demogorge savegely attacked and fed on several of them before the God Squad managed to brake through to the Skrull gods. A heroic battle ensued and Ajak assumed leadership of the team deeming Hercules as incompetent. Ajak managed to survive the battle along with all the other members of the team with the exception of Demogorge who apparently lost his life in battle with the Sl'gur't.