Akemi serves as a foster parent of Jin. Always addressed as 'Oba-chan/old lady/auntie' by Jin, Akemi was an ex-hostess who had a son she lost custody of to her ex-husband. Her face was slashed by a crazed client, who in turn suffered near fatal injuries by a young Jin, having recalled how his grandfather was killed. She has been selling crepes at a roadside stall ever since.

Spoiler

She was seemingly killed right in front of Jin's eyes in a bid to let Jin return to the Amagi Corp., but was later revealed by Mitsugai to be alive, and was given back custody of her son with the help of Amagi Corp.. She received a box of money saved by Jin as a parting gift. Two years later, she came at Jin's request to give him back his grandfather's pendant.

(Wikipedia)