Koneko Toujou

Koneko is a part of a rare species called Nekomata. Her mother was a Nekomata while her father was a human scientist. Koneko father didn't acknowledge her and only ever used her for experiments, her parents soon later died in an experimental accident. However, her older sister Kuroka was hiding the truth from Koneko in order to protect her. Later down the line after after her sisters betrayal, Koneko was taken in by Rias older brother. It was then that Rias gave her the name Koneko and made her a servant. At first, Koneko was traumatized and lossed most of her emotions after her sisters incidents, but Rias would eventually help her regain them. This will only further when she met you.