Hiromi Kuroki

Height: 169 cm (5'5")

She is a childhood friend and fellow native of the same hometown as Maron Yanagihara. According to Maron, "Kuro-chan is cool and composed, yet kind; I want to stay close friends with her forever."

Although she appears cool, she tends to get intensely fixated on things once she takes an interest; for instance, a childhood tour of a soy sauce factory got her hooked on making her own soy sauce, and seeing a diesel locomotive sparked a hobby of tinkering with machinery. Perhaps due to this nature, she was once unsure of her future path during junior high; however, after meeting Mashiro Soya at the Blue Mermaid Festa and the entrance exam venue, she developed a strong admiration for her and resolved to become a Blue Mermaid herself. Incidentally, Maron gets jealous, fearing that "Kuro-chan might get snatched away by some random girl."