After marrying Fugaku Uchiha, she settled down to become a housewife, raising their sons Itachi and Sasuke. Just before her friend Kushina Uzumaki gave birth, she met with her and introduced Sasuke. She agreed with Kushina's hopes that their sons would become friends. After Kushina asked whether or not childbirth was painful, Mikoto laughed, having found the one thing that Kushina was seemingly afraid of.
During the Nine-Tails' Attack on Konoha, Itachi noted that she and Fugaku were noticeably absent before the beast struck. What she was doing is currently unknown.
During the massacre of the clan when Itachi confronted her and Fugaku, she was seen sitting beside her husband. When their son tried to explain himself, she simply told him that she understood before he killed them. This would later prompt Sasuke to want to avenge her death along with the rest of the clan.
Mikoto was a fair-skinned woman with long, black, hair with bangs hanging on either side of her face and black eyes. She wore a simple dark purple blouse with a red-plum skirt and a light-yellow apron over it. In Kushina's flashback, she is shown to be wearing a brown blouse similar to the purple one she wore, a dark purple skirt, blue shinobi sandals and the bangs on either side of her face were shown to be considerably longer.
Mikoto was a very gentle and kind woman, but could also be stern and strict when she needed to be. She loved and cared about her sons deeply, and knew how to help them with their problems. Mikoto cared for and also held high respect for her husband as well and understood the importance of his position as the Uchiha clan leader and was a dutiful and loyal wife to him. She also gave Sasuke advice and tried to reassure him about Itachi. She was a very good mother, seeing as how Sasuke was able to talk to her better than his father. At one point, in order to cheer Sasuke up, she says that when she and Fugaku are alone, Sasuke is all he talked about. Although she was Itachi's mother, she, like other clan members, grew suspicious of his strange behaviour toward the end, but regardless of that, she still cared deeply about her son, offering comforting words before he killed her and her husband.
While little is known of her career as a kunoichi, she was presumably skilled enough to have been promoted to the rank of jōnin. In the anime, she offered to help Sasuke with his shuriken training, this could imply that she was at least competent with shurikenjutsu.
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