Nona

The manager of the Arbiter system, as well as the bartender of Nona Ginta located on the ninetieth floor. She is the boss of Decim, Ginti, Clavis, and all the other arbiters. She has been the manager for 82 years. Nona has a rather overall serious demeanor and disciplines her employees. She administers rulings for who is responsible for each floor under her and corrects any mistakes that they make. Despite her young appearance, she is calculated and is an experienced and knowledgeable arbiter.

(Source: Death Parade Wikia)