Peta

Peta is Null's sister that passed away. She is a main character in the Null & Peta series that likes to cook, but is known for her notoriously awful cooking. Peta has purple, long hair tied into twin tails.

It was initially thought that Peta was struck by the car, but it happened to be Null. Peta had created a virtual world that Null could remain during her unconsciousness. The virtual version of Peta (the robot) is her way of communicating with her sister.