Who is Rittenhouse from Bright Lights, Big City and what is their importance?

Rittenhouse is also a co-worker of the narrator's in the Department of Factual Verification. A middle-aged, fourteen-year veteran of fact checking, his personality is meek to the point of near invisibility. He watches every word and qualifies his statements to cover himself for potential inaccuracies. He is the boss's favorite worker in the department.