Yumeko Tendō, a human fourth-grade student, first appears in the 1985 series' second episode after the yōkai Kagami-Jijii traps her within a mirror, leading to her encounter with Kitarō. She stands 143 cm tall, weighs 39 kg, and has long brown hair with short bangs. She wears a blue dress with white sleeves and collar, white socks, and blue shoes.

Her family consists of parents Masao and Yūko Tendō and younger brother Hoshirō Tendō. Yumeko aspires to become a picture book author. She champions peaceful coexistence between humans and yōkai, aligning with Kitarō's philosophy. This belief guides her interactions, though she exhibits wariness toward certain yōkai; she tolerates Nezumi-Otoko's persistent attentions, occasionally leveraging his interest to assist Kitarō. Her relationship with Neko-Musume is contentious, marked by frequent bickering and a mutual interest in Kitarō.

Yumeko develops a close bond with Kitarō, portrayed as a potential romantic interest. She forms significant connections with other yōkai: her kindness toward Shu-no-Bon inspires his loyalty, leading him to call her an "angel" and ultimately sacrifice himself to save her and Kitarō during the Jigoku Arc finale. She appears recurringly, though not continuously, across the 1985 series, with specific episodes highlighting her involvement in yōkai-related incidents.

A later manga chapter implies off-screen development suggesting she reaches high school age.