Iris Cannary is a young woman who works as an Auto Memory Doll at the CH Postal Company in the city of Leiden. She originates from the rural mountain village of Kazali, where she was born and raised. Her name was chosen by her parents, as she was born during the season when the blue iris flowers were in full bloom across her hometown. The painful memory of being rejected by her childhood friend, Emonn Snow, after confessing her love to him served as a powerful catalyst, driving her to leave home and pursue a new life as a professional ghostwriter. Despite lacking any natural talent for writing, she worked with intense dedication, attending the Auto Memories Doll Training School and eventually graduating to secure her position at CH Postal.

Iris possesses a competitive and determined personality, driven by a strong desire to become the most popular and successful Auto Memories Doll in Leiden. She greatly admires her senior colleague, Cattleya Baudelaire, and aspires to achieve a similar level of success. Her manner of speaking reflects her relationships; she is polite and respectful toward her slightly senior coworker, Erica Brown, but speaks casually and with a sense of familiarity to her male coworker, Benedict Blue. Iris is not afraid to voice her opinions, sometimes coming across as blunt, impulsive, or short-tempered. She can be easily excited by interesting assignments and openly expresses boredom with mundane tasks. While she projects an image of self-confidence, she can also be sensitive and insecure about her past and her professional standing. Beneath her sometimes sassy and tough exterior, she is a caring individual who is deeply dedicated to her friends and family, and she takes great pride in her work as a Doll.

Iris is deeply motivated by her dream of establishing herself as a respected career woman, an ideal she has always admired. She is fiercely opposed to the idea of abandoning her professional ambitions to get married and settle down, which becomes a significant source of conflict with her parents. Another key motivation is her initial jealousy and frustration towards Violet Evergarden, a newcomer whose rapid growth and unique abilities Iris feels threatened by, leading her to question Violet's place at the company. Over time, her primary motivation evolves from simply being the best to finding her own authentic way to connect with others and give voice to their emotions, even as the world around her changes.

In the narrative, Iris serves as a fellow Auto Memory Doll and a colleague to the protagonist, Violet Evergarden. Her role is significant as she represents a more conventional, ambitious newcomer whose personal journey contrasts with and complements Violet's own search for meaning. Her central storyline occurs when she receives a request to return to her hometown of Kazali for a job. Upon arrival, she discovers her parents fabricated the request as a ruse to celebrate her birthday and pressure her into giving up her career and finding a husband. The situation becomes unbearable when she learns her mother invited Emonn to the party, forcing her to relive her painful rejection. After a public outburst, a despondent Iris retreats and confides her past to Violet. This moment of vulnerability allows her to finally reconcile with her parents, using Violet's ghostwriting skills to pen an apology letter that also reaffirms her commitment to her dreams. Later, as technology like the telephone begins to threaten the future of letters, Iris initially dismisses it as an unpleasant machine. However, she has a change of heart when she uses a telephone to help a dying boy named Yuris convey his final messages, realizing that new technology can also serve as a tool to connect hearts.

Iris shares several key relationships that define her growth. Her relationship with her parents evolves from one of conflict, stemming from their traditional expectations for her to marry, to one of mutual understanding and support after they finally accept her career ambitions. Her dynamic with Violet Evergarden is central to her development, beginning with coldness and jealousy, including a suggestion that Violet be fired. This transforms into a genuine friendship and mutual respect after Violet offers her comfort and understanding during the crisis in Kazali. She has a supportive and friendly relationship with Erica Brown, often collaborating with her and showing her respect. While she works alongside Benedict Blue, her tone with him is notably more casual. Her past connection to Emonn Snow haunts her, as his rejection is the original wound that spurred her to leave home and become who she is.

Throughout the series, Iris shows clear development. She begins as a brash and insecure newcomer but matures into a more confident and empathetic professional. By the time of the later film, she has advanced to become the third-ranked Auto Memory Doll at CH Postal Company, behind only Cattleya and Violet, a position she sometimes grumbles about but ultimately accepts. Her understanding of her profession deepens as she learns to appreciate that the core of her job is connecting people, regardless of the medium used. Her appearance also changes over time, with her hair growing longer in later installments, reflecting her personal growth and maturity. As an anime-original character not present in the original novels, her storyline was specifically crafted for the animated adaptation.

Iris's primary ability is her skill as an Auto Memory Doll, a professional ghostwriter who transforms clients' thoughts and feelings into letters. While not a naturally gifted writer, she compensates with her hard work, determination, and dedication to her craft. Her core talent lies in her ability to understand and articulate the emotions of others, which she continues to refine through her experiences.