Specimen 731

Specimen 731 in her "Jane" form

Specimen 731 is one of ten changelings that was captured by the covert Federation agency Section 31 during the Dominion War and trained and experimented on during the Project Proteus program in 2375. Section 31 hoped to create the "perfect spy" by creating changelings that could pass conventional detection methods by mimicking internal organs and other biological aspects of the species they were pretending to be. Unlike her siblings, who were subjected to daily torture to ensure compliance, 731 was a younger changeling and treated differently by the lead researcher assigned to oversee her training and experimentation, Dr. Boucher, who believed in psychological conditioning over physical coercion. Boucher wanted the changelings to develop a strict sense of loyalty to the Federation to ensure they would not turn on their handlers, and 731 studied Federation history and ideals to the point that 731 began to embrace and internalize those ideals.

Under Boucher’s guidance, 731 developed a strong desire to please and demonstrated remarkable adaptability and intelligence. During one of the assessment trials, 731 took on the form of “Cadet Jane Archer,” a human Starfleet cadet, to impress Boucher. This form was strategically chosen based on observations and deductions about Boucher's preferences and his own real-life biological daughter, whose picture he kept in the lab. It also reflected 731's own secret desire to one day join Starfleet, believing that the idealistic Federation would surely accept changelings one day amongst its diverse membership.

Infiltration of USS Kitty Hawk

Twenty-six years later in 2401, 731 infiltrated the USS Kitty Hawk, posing as Captain Roshanara Rahman. The plan originally had been to salvage any of the younger crew and eliminate the rest, and she successfully manipulated first officer Wil Ukinix into setting the ship's auto destruct with her. However, her cover was blown after she attempted to assassinate chief engineer Nathan Richards, and after escaping into the ship's ventilation system, her new mission was to ensure no one made it off Kitty Hawk alive.