Kokoa has dark hair that is slightly wavy towards the ends, and has bangs across her forehead. Her bangs get longer at the sides of her head. She also normally wears a ponytail that is on the side of her head.
Nakamura Hina - Kokoa describes Hina as weird and strange when she talks to Nakamura Hiro. She notes that she's very lonely, gloomy and quiet. Kokoa thinks that Hina really must hate her family. Because she and Hina have grown up together, she easily understands how Hina feels, knowing when she appears to be happy even with her emotionless-looking face.
Nakamura Hiro - In Chapter 29, Hiro talks with Kokoa about Hina, since Hina didn't say much to Hiro. Kokoa tells Hiro how her sense of humour is weird, and how she came up with puns after Kokoa had said she was too gloomy (which Kokoa thought was not funny at all). She notes to Hiro that Hina eats by herself a lot, and barely talks to Kokoa's parents. Kokoa tells Hiro how she is extremely careful when she talks to Kokoa's parents.