Rieko Hinaga

An elderly woman living in the countryside with her granddaughter Airi, whom Keima encounters while visiting his grandparents. The escaped spirit within her causes a ghost-like apparition of her childlike self to appear at night which is initially mistaken to be Airi because of their similarity in appearance. While Keima meets Reiko in the graveyard, Elsee convinces the runaway spirit to leave because it is impossible to resurrect (Reiko now being to old to give birth). In the graveyard, Keima learns that the gap in Reiko's heart was cause by loneliness. Her family and most of her friends are old, have left, or passed away.

However Reiko's apparition, (now assuming her teenage appearance) tells Keima that at least she was able to live out a happy life and departs. According to Keima in the aftermath, the spirit is gone but the gap remains, Reiko has simply accepted the gap and moved on. (Source: Wikipedia - List of Kami nomi zo Shiru Sekai characters)