observer, bystander, onlooker, spectator, eyewitness, viewer, beholder, watcher, testifier, deponent, attester, perceiver, looker-on, witnesser, seer
commander - leader - director - overseer - supervisor - organizer - coordinator - manager - chief - head - controller - regulator - administrator - conductor - guide - pilot - captain - general - field marshal - warden - steward - superintendent - inspector - adjudicator - referee - umpire - judge - arbitrator - moderator - facilitator - arranger - planner - executor
A marshal is a law officer engaged in maintaining public order, security, and ensuring that the law is followed. Historically, marshals were officials responsible for managing the household, overseeing knights, or organizing court services in noble households. Today, in certain countries, marshals refer to specific law enforcement officers like chief law enforcement officers in federal courts or military officers in charge of organizing troops.