Breil was a female Starfleet officer who lived during the mid-23rd century. She served aboard the USS Enterprise under Captain James T. Kirk, in 2269 as the ship's mess officer.
That year, Breil called security, following the panic caused by the shrinking of the ship's crew in the mess hall. She reported the apparent increases in the size of tables, chairs, and silverware, as well as the sudden disappearance of smaller objects like rings and hairpins, which had been noted by women crewmembers. (TAS: "The Terratin Incident")
This character appeared as an off-screen voiceover.
The voice for Breil was provided by Nichelle Nichols.
Breil was originally scripted to appear on-screen, where they were described as a "disturbed looking young [male] officer."