Waver cast a cursory look at Rincewind, as if searching his eyes and actions for an answer to some unspoken question.

"I am," he said, nodding firmly. "Are you?"

Because he knew Rincewind was tough in his own right, but cowards would always be cowards no matter how brave they could seem at times. Somehow, he wasn't surprised that Rincewind would fear Death....then again, who didn't on some level?