He did not sleep.
The Middle Domain did not appear to have a mechanism for sleep in the Lower Domain sense. The shift in ambient light quality that had marked the passage of the first day through its cycle had not produced the specific physical need for unconsciousness that Blue Star's biology had always produced. He was aware of fatigue in the general sense he had been aware of it in the room behind the Fifth Gate's door, the accumulated weight of sustained effort across a long period. But the fatigue did not demand sleep. It existed alongside wakefulness without requiring resolution through unconsciousness.
He sat through the light-shift's completion and into the next cycle's beginning and was aware of being awake throughout.
This was information about the Middle Domain's effect on physiology. He filed it alongside the other information the first day had produced and let the second day arrive.
