Ako Tōma is a student at Chidori High School, sharing classes with Hikari Kokura. She regularly interacts with Hikari during lunch breaks and casual conversations. Ako participates in the school's Tracking Club, reflecting an interest in outdoor pursuits or nature observation. Her social circle includes classmate Marina Tsuji, who also engages in similar casual interactions with Hikari.

Her name, Ako (あこ), has no defined meaning in hiragana. Potential kanji interpretations encompass combinations such as 亜古 ("second/Asia" and "old"), 亜子 ("second/Asia" and "child"), 亜心 ("second/Asia" and "heart/mind"), 亜都 ("second/Asia" and "metropolis"), 亜虹 ("second/Asia" and "rainbow"), 亜恋 ("second/Asia" and "love"), or 亜湖 ("second/Asia" and "lake"). Her surname, Tōma (当麻), translates to "hit/right/appropriate/himself" (当) and "hemp/flax" (麻).