Koura, a demon residing in the Underworld, masters Kiyakudo, a specialized medicine shop. She primarily maintains a human form. Her striking appearance features dark green hair in a ponytail secured with a hairpin, vivid red eyes, red lipstick, and red nail polish, accentuated by three distinctive red dots beneath her right eye. She typically wears a dark green kimono patterned with florals, tied with a light green sash decorated with circular motifs, completed by black socks and sandals, her usual expression carrying a seductive quality.

Her personality blends a seductive, complimentary manner with a deep obsession for creating medicine. She frequently praises the physical traits of humans and demons—like Haruitsuki Abeno's eyes, Hanae Ashiya's ears, or the Legislator's voice—yet views these features primarily as potential ingredients for her concoctions. This fixation sparks states of elation whenever she encounters elements that could advance her research. She expresses strong disinterest in matters unrelated to medicine or shop duties. Professionally, Koura wields extensive expertise in mixing and researching Underworld medicine, leveraging profound pharmacological knowledge to address complex supernatural ailments. For instance, she develops treatments for conditions such as parasitic shrub infestations affecting demons, though such remedies can induce severe pain as a side effect.

Koura maintains key relationships: Shizuku, the Legislator's younger sister, serves as her loyal Kiyakudo assistant. Koura shows consistent kindness and protectiveness toward Shizuku, whose romantic feelings for her are noted by others. She also shares a longstanding friendship with Haruitsuki Abeno, a regular customer, and interacts familiarly with the Legislator, one of the Underworld's three ruling figures.