A fictional hybrid whale based on the real “Loneliest Whale,” known for its unique 55-Hz song, which cannot be understood by other whales. The whale's struggles with communication mirror those of Iris.

Iris’s Deaf grandfather, who inspires her with his passion for Deaf culture and performance. Although he is deceased during the narrative, his past influence and messages remain significant to Iris.

Iris’s Deaf grandmother, who is a bold and dynamic character but struggles with bereavement. Her connections to Iris deepen when they embark on an Alaskan cruise together.

Iris’s hearing mother, who is fluent in sign language but struggles with insecurities regarding her daughter’s ties to the Deaf community. She evolves to better understand and support Iris’s needs.

Iris’s hearing father, who is not skilled in sign language and shares a love for the ocean with Iris. His limited communication with Iris mirrors his tentative bond with her.

Iris’s older brother who drives her to Mr. Gunnar’s store and understands sign language well. He often mediates between Iris and their parents and supports her electronics interests.

Iris’s friend who is also Deaf and comes from a family fluent in ASL. His access to a Deaf community contrasts with Iris’s isolation, making him an important figure in her life.

Iris’s friend from an Alaskan cruise, who is aspiring to be a shark biologist. Bennie embraces Iris’s Deafness without judgment, fostering a genuine and supportive friendship.

A sanctuary staff member in Alaska who supports Iris’s creative projects. She encourages Iris in her pursuit of acoustic biology.

Iris’s teacher at Timber Oaks school, who is unsupportive and resents Iris due to her Deafness. Her lack of understanding contributes to Iris’s sense of isolation at school.

Iris’s science teacher who introduces her class to Blue 55 and supports Iris's interests. She provides genuine care and encouragement to Iris.

Iris’s ASL interpreter at Timber Oaks, who shares a mutual respect and understanding with Iris. He assists in her communication with hearing teachers.

Iris’s well-meaning but frustrating classmate at Timber Oaks, who attempts to sign without proper knowledge. Her actions highlight the challenges Iris faces in a hearing world.

The owner of the antique shop where Iris earns money by repairing electronics. He respects her abilities and provides a supportive environment for her passion.