In "What It Always Is", Yumiko checks around the community to make sure everyone is helping with their chores. She is informed by Alden that Eugene has come up with a plan to salvage the fallen tree and use it to fix the wall. He also suggests to her that they should build up their defenses but she says is not the time as Earl complains about their lack of retaliation against the Whisperers. Suddenly, Brianna tells Yumiko that someone stole the crate of fish from Oceanside during the night. Upon finding out it happened during Magna's shift, Magna was confronted by Yumiko for what she had done. During the conversation, she confessed to her girlfriend that she was guilty of the crime she thought was innocent and left the room to avoid more tension between them. Yumiko is portrayed by Eleanor Matsuura. The character entered the recurring cast beginning with the episode "What Comes After" of the ninth season. However, Eleanor Matsuura was promoted to a series regular starting the tenth season. During an interview with Cynthia Vinney writing for "CBR" Eleanor Matsuura revealed that it feels happy to work for Robert Kirkman and said: "Oh my gosh, it was crazy and a real honor to join such an established show, a huge family that's been just like slaying it for nine years. I mean the fact that we're on our tenth season now is just an incredible achievement. I feel so proud to be a part of it." Ryan DeVault of "Monsters and Critics" praised the work of Eleanor Matsuura and wrote: "Matsuura's character of Yumiko is already making an important impact on "The Walking Dead" cast. Though she has only been in a handful of episodes, there is a lot of foreshadowing that suggests she will have an important part in the coming conflict with the Whisperers." During an interview with Emily Hannemann writing for "TV Insider" Eleanor Matsuura revealed the interest of Yumiko's character development and said: "Yes, it was! I had a conversation with Angela at the beginning of the season where she told me about where she sees Yumiko going and what's going to unfold in the season. One of the things that was mentioned was that Hilltop is going through this huge change with the attacks happening and losing Tara last season, and Maggie is currently not around. I don't think it was ever pre-planned, that Yumiko's like, 'I'm going to be the leader!'