Akane Shinkai

Akane Shinkai is introduced as the assistant of Kamijo, a genius who made a career studying "Innocent Devils." [Spoiler] It is revealed that she was put under surveillance when Akane killed her parents at an early age and felt nothing. She tries to find an answer to "how should I feel when killing a person?" so she follows Kamijo, and together, they face many murderers and other Innocent Devils. [/Spoiler]