Nemu has purple-black hair which she keeps in a bowl cut and a long braid, with to long strands hanging down in front of her ears. She also has purple eyes.
She wears a traditional lieutenant Shinigami uniform, but with the bottom modified into more of a short-skirt. She also wears a red choker around her neck.
Nemu tends to hang back, speak softly, and follow every order Mayuri gives her. When he's not around, she's revealed to be a bit more sympathetic than him. She is concerned about Mayuri's health, despite the way he treats her, and offers an antidote to his would-be assassin, even though he confessed that he didn't spare her Captain intentionally.