Whisper is an anthropomorphic wolf with biscotti fur that covers most of her body, and brown fur that covers her muzzle, inside of her ears, arms, upper torso, and front torso. She has thick black eyelashes and cloudy white fur around her eyes that resemble a mask. Her eyes are cadet blue, although they are often closed to the point of squinting up due to being traumatized by Mimic until the 79th issue. She wears light gray eyeshadow and has a long, bushy tail which ends in several tufts of fur sticking out in various directions. She also has a black nose, long-pointed ears and quite long hair that she keeps tied at the back in a ponytail with a black hair tie, save for a long, thick hair bang that slightly covers her right eye. Her pointed cheeks are a little fluffy. Her fangs protrude from her mouth which is often in a natural frown.

For attire, Whisper wears a cream-colored tube top, light gray leggings, and a dark gray cloak, in which she keeps six Wisp canisters. The cloak also has black and dark gray pockets seen on the shoulders, she sometimes takes off the cloak when off-battle.

Whisper wears an outfit geared towards combat. This includes dark gray arm sleeves with black elbow pads, dark gray and light gray gloves with visible black claws, and dark gray knee sleeves with black knee pads. She sports military-fashioned black, dark gray, and light gray boots.

Whisper is very much a lone wolf, so to speak. Keeping to herself, she prefers to do her own thing and work on her own rather than cooperating directly with others. This is illustrated by the fact that while she assisted the Resistance during the war, she never actually joined or even revealed herself to them. Despite this, people like Sonic are able to convince her to come out of her shell and collaborate with others, like when she joined the Resistance on a mission to liberate Angel Island, during which she showed high coordination with her teammates and proved quite helpful to them. Over time, Whisper has grown more confident with her new friendships, which has caused her to reveal her most emotional side in the worst of situations. Still, she tried to act alone, fearing for the fate of her friends should they get entangled in her affairs. Once she realized people were trying to help her and she was pushing them away, she promised to work on moving on from her past and to become a better friend and teammate.