|File:Phlox on Defiant.jpg|
|Caption:||Doctor Phlox in 2155|
Phlox was a Denobulan military doctor serving aboard the ISS Enterprise. He was amoral and sadistic; he carried out brutal, horrific experiments on living beings, including sentients, in the name of medical research for the Terran Empire, and designed various methods of torture for the Empire's use, especially aboard the ISS Enterprise.
Phlox and Major Malcolm Reed together designed a prototype for the agony booth. He also supervised the torture of the Tholian captured by Commander Jonathan Archer to determine the location of the Terran ship. When Captain Maximilian Forrest regained command and ordered Phlox to kill the Tholian, who was sending out a distress call to other Tholian ships, Phlox happily complied, and even expressed impatience when the Tholian took too long to expire. When several Tholian ships arrived, alerted by the distress call, and attacked the Enterprise, Phlox escaped in an escape pod just before the Enterprise's destruction and made it to the USS Defiant. (ENT: "In a Mirror, Darkly")
While aboard the Defiant, T'Pol told Phlox of the research she had done on the ship's historical database. She was fascinated to discover that in the mirror universe, a United Federation of Planets was formed by Earth and other alien worlds, and that all members were regarded as equal. Phlox viewed such talk as subversive and dangerous, and felt that Archer should restrict access to the historical database.
Denobulans were perceived by most Humans to be pacifistic with no real desire for war, power or revolutionary ambitions towards the Empire. It was for this reason that Commander Archer allowed Phlox to remain on the Defiant while all other alien crewmembers were transferred to the ISS Avenger.
When approached by T'Pol and Soval to help them destroy the Defiant and stop Archer from crowning himself Emperor, Phlox resisted. He genuinely respected Archer's abilities as both an officer and warrior. Furthermore, he agreed with Archer that the current Emperor was corrupt, incompetent and responsible for the Empire's continuing losses, and that Archer might be able to turn the tide in favor of the Empire. When both T'Pol and Soval insisted that Archer's plans were delusional, Phlox pointed out that with the Defiant, Archer's seemingly delusional plan to become Emperor could become a reality. Furthermore, Phlox threatened to report their conspiracy to Archer.
T'Pol and Soval pointed out that if Archer were unsuccessful, both he and his crew would be executed for treason. Furthermore, they pointed out that if one were to save the Emperor's life, by custom, the Emperor would grant that person anything they desired, such as a medical laboratory with unlimited funding and possibly concubines as well. The latter argument seemed to convince Phlox to help stop Archer.
Phlox attempted to sabotage key components of the Defiant, allowing the Avenger to attack and gain an early tactical advantage. However, Commander Charles Tucker discovered Phlox's treachery and was able to stop him and restore the ship's weapons and shields in time. This allowed the Defiant to gain the upper hand and destroy the Avenger. (ENT: "In a Mirror, Darkly")