Natural Killer Cell
Nk cell black
 JAPANESE NAME ナチュラルキラー細胞
 ROMANJI Nachuraru Kirā Saibō
 STATUS Active
 GENDER Female
 SPECIES Lymphocyte Cell
 OCCUPATION Infected Cells Identifier/Killer
 MANGA DEBUT Chapter 11

Natural Killer Cell (ナチュラルキラー細胞, Nachuraru Kirā Saibō) is a minor character in Cells at Work! BLACK.

She is a white blood cell, specifically a Lymphocyte (Natural Killer Cell). She is tasked to identify, track, and kill viruses and infected cells by moving freely from tissue to tissue.


She is a muscular and fit woman. She wears a tank top, shorts, and boots.


NK Cell has heightened senses compared to other lymphocytes, and it is her task to detect disguised or hidden infected cells and viruses.

  • Overall Abilities: She is extremely skilled at killing pathogenic cells. She can single-handedly finish the tasks of a few killer T cells. She is swift and strong and capable of breaking tissue walls during fights.
  • Saber Proficiency: She can professionally wield a saber sword.
  • Cytotoxic: NK Cell can kill aberrant or normal cells under discretion.
  • Adaptive Memory: She can remember previous infected cells and their attack moves for easier termination in case one of them appears again in the future.
  • Transmigrate: She is able to move freely through tissues to reach her target faster.


  • Natural killer cells and killer T cells resembles brothers-in-arm because of their complementary roles for each other.
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