Yumi's Cells

Nam Joo-hyuk, Chief Nam.

Hong Na-ri (ep. 7–8)

Yoo Da-eun, part-time worker at Jeju branch of Daehan Noodles.

Yoo Babi, Yumi's co-worker and boyfriend.

Nung-cheol (Voice)

Baek Na-hee

Chae U-gi, Yumi's co-worker and unreciprocated crush.

Ja-young, Babi's ex-girlfriend

Kim Yumi, an ordinary office worker.

Goo Woong, a game developer and Yumi's second boyfriend and Sae-yi's love interest. Jun Ho-young as teen Goo Woong

Shin Soon-rok, employee of a publishing company in charge of Yumi's works and her boyfriend.

Kim Joo-ho, the lead writer

Tongue Cells (voice: )

Seo Sae-yi, Goo Woong's colleague. She dreams of becoming the best game art director.

Ruby, Yumi's co-worker who prides herself on mastering various dating techniques.

Yumi's mother

Yumi's father

Control Z, an illustrator who works with Yumi.

Ahn Dae-young, editor-in-chief of Julie's Literature History.