" He looked up. I had seen him bare-chested before, but this was the first time I had really noticed that he had no navel. His sarx—the warm gold of brass— was taught and seamless over slabs of muscle, limned by the dim light from the lamp.
“Paige,” he said, his tone questioning.
I realized I was staring like a gamal at him.
“Sorry,” I said, face warm. “You just don’t have—” I indicated my own abdomen. “But you wouldn’t, I suppose.”
Rephaim were not born. He had never been tethered to a womb, nor grown inside someone else. When he had first emerged, alone, he had looked exactly as he did now.
“You are curious about the other differences.” Arcturus closed his book. “There are none. Externally, at least.”
“But Rephaim don’t reproduce,” I said thinking aloud. “So you probably don’t have a— "

― Samantha Shannon , The Mask Falling (The Bone Season, #4)