Sima is a slender kenku woman with glossy charcoal feathers that soften to warm brown around her throat and wing joints. Her rounded beak is small for a kenku, and when she laughs, a row of surprisingly neat pale teeth shows behind it. She wears a weather-faded leather coat over a patched grey shirt, with one sleeve carefully re-stitched in bright red thread. Her boots are mismatched but well maintained, and a small brass prayer bead is tied to her belt beside her thieves' tools. She keeps her feathers meticulously groomed, except for a stubborn tuft above her left eye that always leans forward.

Sima is observant, soft-spoken, and unsettlingly earnest. She collects voices the way other people collect keepsakes, repeating a person's laugh or favorite phrase when she misses them. Despite her criminal habits and chaotic impulses, she is quick to offer help, quick to believe an apology, and painfully eager to be wanted. She can be warm and funny when relaxed, though her humor often arrives in the stolen voice of someone who once hurt her.

Sima was raised in the back rooms of a roadside shrine, though no one there ever admitted to being her family. The priests called her a blessing when offerings were good and an omen when they were not. She learned prayers by imitation, repeating the voices of the devout until the words became indistinguishable from her own. When a fire consumed the shrine's outer forest, the priests blamed her strange voice and drove her away. Sima remembers the flames, the smell of resin, and a second voice giving her instructions from somewhere beyond the trees. She does not remember starting the fire, but she has never stopped wondering whether she did.