The Stargazer is a mysterious, old, priestess-like figure, that is used for tracking the actions of contractors. Her real name is Hoshimi, but she is often referred to as "the Stargazer". She lives at the National Astronomical Observatory of Japan. She rarely speaks, but when she does, she speaks in riddles. She is also immune to Amber's Contractor abilities, and is able to talk while time is frozen.
(Source: DTB Wiki)