She is Narumi's classmate. She was the first one to initiate a conversation with Narumi and also the one who introduced Narumi to Hanamaru Ramen shop and the NEET Detective Team.
Currently, her parents are divorced and both the parents live in seperate areas. She also has an older brother, Shinozaki Toshi, who was imprisoned and rehabilitated because of an addiction to drugs. In the Light Novel, Ayaka suffers an amnesia early in the story. In contrast, the anime had Ayaka be hospitalised at the final episode during the same arc.