Odo was a Changeling, one of a hundred infants of that species sent out to explore the galaxy and compelled to return later in order to share their experiences. He served as chief of security aboard the space station Terok Nor, later known as Imperia Nolus. Odo was one of the "Hundred Changelings", a group of one hundred newly-formed Changelings that the Founders sent out into the galaxy, in order to gather information and explore, and did not expect to return until the 6580 N.E.