“Don't be silly. I'm going to be with you all the way. No matter what…”
Sachiko Yagami (夜神•幸子, Yagami Sachiko) is the wife of Soichiro Yagami, as well as the mother of Light Yagami and Sayu Yagami. She is oblivious to Light's ownership and use of the Death Note.
Sachiko has short brown hair, cut above her shoulders, and dark colored eyes. She tends to dress casually, though rather nicely.
Sachiko is a kind woman that deeply loves her family. She loves her husband, Soichiro very much and worries about his well being while he works on the Kira case. When Soichiro is hospitalized due to a stress related heart attack, she is frequently by his side to care for him. Sachiko is very proud of her son, Light and congratulates him on his good grades. When Sayu is wheelchair ridden due to emotional trauma caused by her kidnapping, Sachiko aides her recovery, encouraging her and taking her for walks outside.
She is the first seen waiting for Light to show her his exam grades.
Obata said that he had no real concept behind the design of Sachiko; he said that he encountered difficulty in drawing female characters who were not the main characters. Ohba did not include Sachiko in the final chapter of the manga, but stated that someone of the Task Force would likely tell her that Light and Soichiro died in order to stop Kira. The Task Force members would never let the world know the truth about the Death Note case.