While otherwise the novel The Broken Blade by Simon Hawke is offensively awful, it does contain the following passge describing a female mul, which may or may nor help the players of my campaign visualise Raina better...
"Her head was completely bald, accentuating the pointy, swept-back ears that lay close against her skull. Her eyes were yellow-gold, deeply sunken and hooded by a prominent ridge of brow. Her mouth was wide and thin-lipped, her chin slightly pointed, and her cheekbones high and unusually pronounced. Her nose was not as wide as that of male muls, and it was blade straight. Though Ankhor had seen her fight before, he had never seen Kah up close, and he was surprised to find that she was beautiful - in a terrifying way.
"Her shoulders were almost twice as broad as his, and her chest thick with muscle, making her breasts look small. She had almost no fat on her at all. Her powerful back muscles fanned out from her sides like wings, accentuating a narrow and extremely muscular waist. Her abdominal muscles stood out in sharp relief, and her long arms were corded with thick muscle. Her thighs and calves looked as if someone had taken a chisel to them."
Laurence J Sinclair