|First appearance||Class Period 11 (manga)
Class Period 6 (anime)
|Voiced by||Yuri Amano|
|Age||Possibly 31/32 Flashback (manga)|
|Notable relatives||Rin Kokonoe (daughter)
Unnamed uncle (deceased)
Unnamed aunt (deceased)
Reiji Kokonoe (cousin)
- Kokonoe Aki (九重 秋?)
Rin's late mother and Reiji's older cousin. Abandoned by her boyfriend when she became pregnant and refused to have an abortion, Aki Kokonoe chose to carry her child to term and undertake the difficult task of raising her young daughter on her own. Despite the fact that her decision to become a single mother had turned her into the black sheep of the family, the kind-hearted Aki never harbored any resentment towards them or her child's father, believing it better to forgive and forget than risk living a life consumed by anger and hatred.
When Rin was five years old, Aki welcomed her then-recently orphaned younger cousin, Reiji, into her home with open arms. Though initially just as cynical towards and mistrustful of her as he had become towards all adults, her gentle, quirky nature and visible affection for her child soon won him over, so much so, in fact, that he fell in love with her. Though initially reluctant to return his feelings due to their age difference (13 years older than Reiji) and status as cousins, she eventually entered into a relationship with him that was, by all appearances, a happy one, and the three of them became a family.
A short time later, however, Aki was diagnosed with Stage 2 lung cancer during what was supposed to be a routine medical exam, an illness that was later on revealed to have been complicated further by Rin's birth, which was the entire reason why she was pushed by her boyfriend to abort Rin in the first place. Upon learning that the amount of money needed to keep her alive for several months could be used to provide for Rin for many years to come, she decided to make the second great sacrifice of her life for the sake of her child by foregoing treatment in order to be able to financially support her daughter and kept her illness secret from everyone for some time. When her situation finally became known to Reiji and she conceded to treatment in light of the ability to financially contribute to their household he had since gained, her cancer proved to be far too aggressive and advanced to deal with. After two months with no improvement, Aki's request that she be allowed to go home was granted. While she hoped she could stay alive long enough to see Rin enter grade school, Aki succumbed to her illness well before then and died, her daughter having remained at her side until the very end.
Though she died more than two years before the opening of the series, Aki remains very much alive in the hearts of Reiji and Rin, whose memories of her continue to influence their lives and shape their actions, for better or worse.