When King Sarengo of Riftgard attacked Brockhall with his Ratguard troops, Berussca and her children killed all but six of the rats. Sarengo broke Berussca's spine, but she in turn mortally wounded Sarengo with her deadly fangs. They both died in Brockhall and their remains were later discovered by the Redwallers.
Berussca's name is seemingly derived from the Latin word for snake, berus.
Berussca and her daughter Sesstra are the only named female adders in the series.