| Name: Cassie O'Brien |
| Human |
| Partner: Chester |
| Element: Shadow |
| Age: 26 |
| Birthday: July 30, 1989 |
| Hometown: Canada |
| Reference: Deviantart |
Cassie "Cass" O'Brien is a bonded human currently a DEVIL research subject. She volunteered for bonding at Facility 66 and is bonded to Chester, a shadow demon.