Miko was of average height for a teenager and had an attractive figure, including D-cup sized breasts. She had long auburn hair that she usually kept loose and occasionally had tied in a ponytail.
After her transformation into a Devilman, Miko gains a sturdy figure, her hair gaining a dark auburn color now pulled back in a braided ponytail, and eyebrows that look thick and assertive, which complements the change in her personality. Her skin also becomes of a darker shade.
As a Devilman, Miko gains a spider-like body and features. Her skin turns brown and her eyes split into four, her platted hair spikes up and large mandibles form around her mouth. Her breasts twist round to her back and the nipples extend into spikes, she has four long and twisted legs with spikes protruding from them and a large thorax at the back.
In the beginning of the series, Miko had a kind-hearted personality and showed respect and kindness to her childhood friends, Akira and Miki. But deep down, she had a deep jealousy of Miki due to her being better than her in track and outshining her. Even the nickname Miko felt like a burden as anyone who used her given name would confuse or mistake her for Miki Makimura. She also had a unquenched sexual thirst and found herself attracted to both Akira and photographer Koji Nagasaki. She passionately watered the flowers outside her home daily, which brought her to the attention of Kukun, who she quickly (and tragically only briefly) made close friends with, and may or not may had liked back after his heartfelt rap. After his death she kept his distinctive glasses to mourn him. She also seems to have a strained relationship with her grandmother.
After becoming a Devilman, Miko became arrogant, brash and tomboyish, blinded by the desire to beat Miki no matter what. Her sexuality wakened more and she found herself taking joy in exerting her power and humiliating other girls. She also became negligent and stopped watering her flowers, to the point where they died. However, after Ryo's betrayal, she confesses that despite her jealousy, she still loved Miki. In her final moments, she sounded much like her kind former self, making amends with Miki and begging for Miki's life to be spared until her very last moments.
Before becoming a Devilman, Miko was 3rd in the Track and Field Club, and everyday after school or on weekends, she would practice her running everyday.
After becoming a Devilman, just like Akira and Koda, Miko's body was enhanced giving her superhuman abilities, such speed, agility, endurance, and strength. In her Devilman form, she can jump and use her claws for combat.
Kuroda has been friends with Miki Makimura and Akira Fudo since childhood. However, as they got older, and Miki got better at track and field and got overshadowed by Miki, she gained the nicknamed Miko to differentiate between them. In high school, while still part of the track and field team as the third best runner, the comparisons she had with Miki caused some tension that Miko kept to herself. Whenever she had the opportunity, Miko would water the flowers outside her building while dealing with her grandmother. One day, she encounters the label recycler Kukun and brushes him off when he asked for Miki.
- Miko's nickname comes from the manga character Mikiko Kawamoto, who makes a cameo role at the end of the series. However her actual name, Miki Kuroda, originally belongs to a character from the Go Nagai manga Susanoo.
- Her personality, sexuality and overall domineering character seems to be strongly indicative of Aoi Kurosaki from the Devilman Lady manga, who likely served as a basis for Kuroda.
- Before her transformation, Miko was usually seen watering snapdragons, which symbolise both graciousness and deception/concealment; referring to how she doesn't seem to mind always being second to Miki, but deep down she is actually resentful of never being able to surpass her.