Nao Yasumori is a supporting character in the anime series Shiki. She is the wife of Mikiyasu Yasumori and the mother of a young son named Susumu. Before moving to Sotoba, she had a difficult childhood: her parents were alcoholics and abandoned her when she was six years old. This past left her with a deep fear of loneliness and a desperate need to hold onto the family she eventually built.

Nao is a gentle and reserved woman who values her household above all else. Her deep love for her husband and son is the central motivation for her actions. However, her devotion becomes twisted after she is turned into a shiki. Shortly after her death, she rises as one of the undead and begins killing her own family members one by one, acting under the misguided hope that they will also rise as shiki and remain with her forever. She first kills her son Susumu, then her husband Mikiyasu, and finally her in-laws Setsuko and Tokujiro. None of them, however, return from death. Frustrated and jealous, she then targets the main Yasumori household and kills her sister-in-law Junko.

Nao's role in the story is that of a tragic antagonist whose actions stem from a broken past and an overwhelming fear of solitude. She does not have close relationships outside her family; her bond with the other shiki is minimal, and she acts largely on her own. Her development is a descent into possessive madness, as she prioritizes keeping her family together over their survival. She has no special abilities beyond those of a typical shiki: superhuman strength, vulnerability to sunlight and stakes, and the need to feed on blood. Her end comes when she is tied up outside and exposed to the rising sun. As she burns, a human takes pity on her and drives a stake through her heart to end her suffering.