Shield strength

A wild frenzy now seized the Brown fighters, who all turned their attention back to Garth. His circle of protection was stunned by volley after volley of spells so that he was forced to stagger backward. He saw through the haze of explosions that Norreen, moving as if she was nothing but a blur, had thrown herself into the fray with sword drawn, leaping upon a Brown fighter and dispatching him with a quick slice to the throat.

(...)

Garth moved to black the spell against her but the volleys from a dozen fighters, some of whom were obviously fifth-rank or better, were too much. Finally he broke his own protection for an instant to strike the terror down that held her and she scrambled away on hands and knees.

***

Arena, Chapter 4