She is of Japanese descent and her family has been in Beacon Hills for many generations.
Her husband, who is Korean, took her family name because she was the only surviving member of her family line, the last Yukimura (before Kira).
While they've not said it on the show, according to a 2016 interview with Creator Jeff Davis, Noshiko is a Celestial Kitsune. This type is also known as "Light" or "Heaven."
Noshiko was born sometime in the 12 century AD. This would place her birth in the Heian Period in Japan.
In 1943, Noshiko was locked away in a United States Internment Camp for Japanese-Americans called Oak Creek.
She was held prisoner under Executive Order 9066 which suspended the U. S. Constitution and took away the rights of thousands of American citizens.
While at the camp, Noshiko fell in love with Corporal Rhys, a young army medic stationed there. She helped her fellow prisoners by stealing food and medicine from the Army and Rhys looked the other way to protect her.
When an epidemic of pneumonia swept through the camp, it was learned that the doctor had been stealing and selling the drugs needed to treat the prisoners.
A riot ensued in which Noshiko was shot several times. Despite her ability to heal, the bullets left her so weakened that she appeared dead. Rhys was badly burned and died a short time later at Eichen House.
As her body was being taken with the rest to be burned as a way to cover up what had happened at the camp, Noshiko prayed to her ancestors to send a Nogitsune to inhabit her body so that she could seek revenge.
Instead it chose to inhabit Rhys' body and then proceeded to kill everyone at the camp and at Eichen House.
Noshiko managed to kill him and took the spirit of the Nogitsune (in the form of a fly) and buried it beneath the Nemeton.
After breaking her tails in her second battle against the Nogitsune, Noshiko describes herself as "technically" a Kitsune.
She seems to have the same abilities as her daughter, causing a tiny bit of foxfire as she changed a light bulb. Later she confronts the Nogitsune saying it "knows" her and that she will kill it. She can also summon and seems to control the Oni. (Read More...)
She breaks two knives, which her husband calls her "tails," in order to summon the Oni. (Read more...)
She visits the spot where Rys' body is placed and the Nogitune uses her tail to slice open his abdomen to release a swarm of flies (Read More...)
She uses the Oni to see if the Stiles they pulled out was the real Stiles, and later she goes to Oak Creek ready to kill the Nogistune, but the dark spirit uses the tail stolen from her to control the Oni instead of her. (Read More...)
After the Oni are taken from her, she tells Kira the only way to beat the Nogitsune at his game is to make "a divine move." (Read More...)
Noshiko decides her work in Beacon Hills is done after the defeat of the Nogitsune and wants to sell the house and move the family back to New York. (Read More...)
She helps Kira "kill" Scott with her foxfire. She and Melissa McCall search for the Benefactor and is injured as they face off with a berserker. She was airlifted to Palo Alto, California for treatment. (Read More...)
She appears in a vision to Kira as she tries figure out how to heal herself and later presents to her daughter her first "tail." (Read More...)
While stuck in traffic on their trip in New York, she tells Kira the tale of the ghostly "Night Riders." (Read More...)
She attacks Kira at the school and provokes her daughter's fox spirit into revealing itself, it nearly kills her until Ken stops Kira. (Read More...)
She gives her daughter advice on how read Valack's book by telling her to read it backwards. (Read More...)
She encourages her daughter to go through with the skinwalker's test. When she fails, Noshiko prepares to fight the skinwalkers to protect Kira. (Read More...)
Noshiko's sword was able to harm the Nogitsune. It seems mystical in nature but it is unclear if the object itself possesses powers or if the person wielding it supplies its magic.
Very little is known about the origins of the sword. Noshiko had this sword in her possession when she was at the Oak Creek internment camp in 1943.
She used it to stop the Nogitsune. After stabbing the body and excising the spirit, the katana shatters to pieces. She buries it in the basement walls of Eichen House along with Rhys' body. (Read More...)
Kira uses the katana to fight the Oni and the Nogitsune. Read More...)
After Scott bites the Nogitsune/Stiles, Kira stabs him through the heart. This time the Nogitsune body shatters and the sword stays whole. (Read More...)