Rapid Response Team 59 - the "Fifty-Niners" - were a Starfleet Special Operations unit stationed aboard the USS Monitor. They were involved in several covert actions during the Dominion War. Between 2374 and early 2375, their commander was Lieutenant Therav th'Shan. Lieutenant Chen Yan replaced th'Shan when he became the Acting Chief Tactical Officer. (Eighth Fleet RPG)
By the second end of the war, the unit had become integrated more fully with the ship's tactical and security personnel, as the casualties mounted.
In 2374, the unit was infiltrated by a Founder posing as a squadmate. The Founder remained with the unit for some time before being detected, resulting in a sabotaged mission and the death of Assistant Chief Tactical Officer Lieutenant Enrique Mendoza by friendly fire. It is considered either heroic or lucky that half of the team survived.
In 2375, RRT-59 and RRT-81 liberated a prisoner-of-war camp in the Chin'toka region, while Takeda Shingen and Midway drew fire from the Jem'hadar and the Breen. Among those freed, was (then) Chief Petty Officer Noelle Connor. Midway, disabled by a Breen energy-dampening weapon, was lost with all hands.
This is collective background information for members of the (Eighth Fleet RPG).