This person is part of a secret organisation that is called "The Angels". As the name suggests this person is named after an angel. Azreal. The angel of death.
For personality I took the 'Angel or death part' quite litterally. While in religion Azreal is described as compassionate. This person is a phycopathic killer when in combat. With pent up anger, from being bullied and picked on he kills, shoots and maims his way through whoever gets in the way of his mission or contract.
