Komui's younger sister, and assistant Head Officer. She is Chinese, and 16 years old. Her parents were killed by an Akuma when she was very young. Because she is an Accommodator, the Black Order took her away from her only remaining family member (Komui) to Headquarters against her will. For three years she was never allowed to leave the place, which felt like a prison to her. Because she attempted suicide, she had to be restrained and tied to her bed. However, once Komui joined the Black Order, Lenalee became more at ease in the Black Order. She once told Allen that her "world" consists of her friends and family; if something terrible ever happened to them, she would be devastated.
She is an Exorcist whose anti-Akuma weapon is a pair of boots, "Dark Boots". That, when invoked increases one's speed and strength greatly in the legs. (Source: Wikipedia)