Sayu Yagami

Sayu has long, chocolate-brown hair that spills past her shoulders and matching brown eyes. In the early part of the story she ties it back into a ponytail, leaving a fringe to one side and loose strands along her cheeks. By the time she reaches adulthood she lets the hair hang free, the bangs still drifting toward the right.

Early on, Sayu behaves exactly as a girl her age might, glued to programs featuring the idol Hideki Ryuga and leaning on Light for help with her math homework. She idolizes her brother, certain his sharp mind will carry him into a fine career in detection. The two start out close, though the bond cools as Light sinks deeper into his life as Kira; even then, he guards a tenderness for her that he shows almost no one, a soft spot Ryuk takes note of. College brings a steadier, more self-reliant Sayu who no longer needs her brother's tutoring. That maturing is cut short by her abduction, an ordeal that leaves her mute and withdrawn. Lighter notes from supplementary material record her fondness for shoes and her distaste for alcohol.

At the opening of the story Sayu is fourteen, a third-year pupil at Eishu Junior High, and her involvement seems trivial. Yet she sets a fatal chain in motion when Light volunteers to carry a change of clothes to their father in her place; the errand puts him in the path of Naomi Misora, whom he murders upon learning she was Raye Penber's fiancee. In the second half she has moved on to university when the Mafia snatches her and spirits her to the United States, holding her to force the task force into surrendering the Death Note in its keeping. Acting on Light's instructions, Soichiro hands the notebook over to ransom his daughter, and she is brought home to Japan only to retreat into shock and spend a long stretch confined to a wheelchair. Her last appearance lands at her Coming of Age ceremony, with the author deliberately leaving her true state of mind for readers to judge. Across other versions she recurs in varied forms, cast as a devoted fan of Misa in the stage musical and aged up in the television drama, where the loss of the siblings' mother in childhood reshapes the family's story.