Sailor Pluto is the Guardian of Time in Bishoujo Senshi Sailor Moon, serving as a mysterious and solemn protector of the Space-Time Door. She is one of the Outer Sailor Guardians and is closely associated with Princess Serenity's future legacy. Often portrayed as calm, reserved, and deeply loyal, she watches over timelines and forbids unauthorized travel through time. Her role is crucial in safeguarding the flow of history and supporting the Sailor Guardians during major conflicts.