Brightbill is a young goose who becomes Roz's adopted son after he imprints on her upon hatching. Despite being teased by other goslings for having a robot mother, he loves Roz and grows into a natural leader during his journey away from the island and back.

Loudwing is an elderly goose who aids Roz in caring for Brightbill by sharing her knowledge and advice. She is practical and immediately accepts the relationship between Roz and Brightbill.

Mr. Beaver is one of Roz's early friends and advisors. Skilled in construction, he helps Roz with various tasks and innovations, including building a prosthetic foot for her.

Nettle and Thorn are young bears who initially act as antagonists to Roz but later become allies after Roz saves Thorn's life. They learn to trust Roz and become part of the community that helps her.

Chitchat is a talkative young squirrel who becomes Brightbill's first true friend. She enjoys the company of Roz and Brightbill, highlighting the normalcy of their family life.

RECOS 1, RECOS 2, and RECOS 3 are combat robots sent to retrieve Roz. Unlike Roz, the RECOS do not adapt or learn from experiences, and operate strictly under orders, making them less capable of handling unexpected situations.

Various animals on the island become a community that teaches Roz how to live among them. Initially wary, they grow to admire and support Roz, becoming integral to her experience and adaptation.