The chain tightens around Mar's neck a bit, and glows as it draws energy from the dome. As the smoke enters Mar's body, he should feel an overwhelming sense of euphoria. A powerful sensation of pleasure will make just about anyone much more docile as the process completes. Inside his mind, a new entity sifts through his memories, and begins trying to remove chunks of them. By taking out and inserting memories, as the entity desires, a new thrall will literally not know anything but servitude of The One.
In truth, Ike never went to any heavenly place. It was just fake memories implanted in him, while he was in the state of euphoria. With he right memories, one could believe they spent much more time in this place than they really did. Reconstructed memories, as well as a spirit to ensure loyalty, was all it really took to make an obedient convert that would bring more to The One.
The attempted constructed memory should make Mar believe that he wanted freedom from his greater half, and The One saved him, and he would be able to do what he wanted without fear of being reabsorbed by the other Highest. He still had his memories of the bar, but before then, the spirit attempted to implant fear for the other Highest inside Mar. Exaggerating any worried Mar might have of being removed after he left the bar. The spirit within could enhance his abilities, especially if he got out from under the being that controlled the Bar. Loyalty to The One would bring physical happiness, while thoughts of deception or treason would bring pain, but no thrall was ever aware that it was the spirit within causing such things. It was just a fact of life for them.
The One knew that what he found would be a lot to take in. He wasn't yet sure if or how he might use it to gain power from or over the other Highest. Defeat over Crayak didn't mean that he could beat just anyone, and he knew that. After all of this was done, the necklace would loosen.