Nagi is the barista at the Time of Eve cafe. She carefully manages the coffee shop and enforces the rule that there must be no discrimination between humans and robots. Nagi is occasionally unsure of how to handle some of the situations that occur in the cafe, leaving open the question as to whether she is an android for most of the series. It is eventually revealed that, as a child of five, she is the human that the Ethics Committee injured in the notorious Tokisaka Incident 8 years prior to the series.

Source: Wikipedia