'Tiefling' has little to no linguistic significance to him, and the sharpening of the frown he shoots at her should inform her as much.

"Universe," he repeats with slow, deliberate stress distributed evenly over all consonants. "Brane. Separate reality." The intensity of his pointed stare abruptly disperses as he looks away, shaking hair from his eyes in a brusque, involuntary motion. His tone becomes wry, quietly self-derisive. "Spacetime is terribly malleable these days, haven't you heard?"