Momoe Sawaki is one of the main characters in the anime Wonder Egg Priority. She is a fourteen-year-old girl who is often mistaken for a boy due to her tall stature, short auburn hair, and broad shoulders. She has a distinct beauty mark under her left eye and dark green eyes. Despite her androgynous appearance, she clearly identifies as a girl and is deeply distressed when others misgender her. She attends an all-girls school and is popular among her female classmates, which sometimes adds to her discomfort because she feels that their admiration is based on a mistaken perception of her as masculine.

Momoe has a calm, serious, and mature personality on the surface. She is kind-hearted, polite, and thoughtful, often acting as a voice of reason within the group. She displays a strong sense of justice and is quick to defend those she cares about. Beneath her composed exterior, she carries deep insecurities and unresolved trauma related to her appearance and her past friendship with a girl named Haruka. Haruka was the first person to fully accept and encourage Momoe as a girl, but their relationship took a difficult turn when Haruka confessed romantic feelings and asked Momoe to touch her. Momoe, caught off guard, rejected her outright. Shortly afterward, Haruka died by suicide, and Momoe has carried guilt over their final interaction ever since. Her primary motivation in the story is to save Haruka through the Wonder Egg system and to make up for her regret.

In the Egg World, Momoe fights using a spear-like weapon that is suggested to be derived from an umbrella, as it can unfurl into a canopy that serves as a defensive shield. She also carries a pomander that hatches into a crocodile-like creature she names Panic, which assists her in battle. As she spends time with the other protagonists, Ai Ohto, Neiru Aonuma, and Rika Kawai, she gradually learns to feel more comfortable showing her true self. Her bond with Ai is particularly significant, as Ai is one of the first people since Haruka to accept Momoe as a girl without hesitation from the start. Momoe is also the niece of Shuichiro Sawaki, an art teacher who plays a role in the larger story. Throughout her journey, Momoe confronts her own identity, her feelings about being perceived as masculine, and the lingering guilt from her past, ultimately moving toward greater self-acceptance.