Introducing... Olivia

We first meet Olivia as she flees her tormentor, Shah Amurath. Her initial introduction is quite brief,

From the dying steed there staggered up its rider, a slender girl in sandals and a girdled tunic. Her dark hair fell over her white shoulders, her eyes were those of a trapped animal.

From "Shadows in the Moonlight"
Page 209. "The Complete Chronicles of CONAN"

We do get a further description a few pages later when CONAN eyes her up,

...he began to gaze at his fair companion with more interest than previously, noting the lustrous clusters of her dark hair, the peach-bloom tints of her dainty skin, and the rounded contours of her lithe figure which the scanty silk tunic displayed to full advantage.

From "Shadows in the Moonlight"
Page 215. "The Complete Chronicles of CONAN"