Dr. Crell Moset was the chief exobiology specialist on Cardassia Prime, certified to perform all surgical procedures. The foremost exobiologist, Dr. Moset was the Chairman of Exobiology at the University of Culat in 2371.
During the Occupation of Bajor, Dr. Moset was practicing medicine on the Bajoran homeworld. Without the resources to try traditional methods, Moset experimented with procedures that never would have occurred to him under ordinary circumstances. As a doctor on Bajor, Moset found the simplest tools, such as scalpels, were the most effective because modern equipment removed a doctor from his subject. It was by these methods that he accidentally discovered the cure for the Fostossa virus epidemic, saving thousands of Bajorans' lives and for which he won the Legate's Crest of Valor.
What was unknown outside of Cardassia and Bajor, however, was the fact that all of Moset's experiments were performed on living people. Thousands of Bajorans were killed in his so-called hospital, including USS Voyager crewmember Ensign Tabor's brother and grandfather. Many of his studies included experiments such as blinding his "patients" so he could study how they adapted, or exposing them to polytrinic acid just to see how long it would take for their skin to heal.
The most horrific part of Moset's experiments was the method used to cure the Fostossa virus epidemic, which was accomplished by infecting hundreds of people so that he could experiment with different treatments. According to Starfleet records, Moset purchased many biochemical agents, including every known strain of the Fostossa virus – a typical procedure in the development of vaccines. However, he didn't ask for any of the enzymes normally required for synthesizing a vaccine. Four days after he received the virus samples there was a minor outbreak of Fostossa in the vicinity of his hospital. Prior to that date there had not been a single case in the entire province.
In 2375, Dr. Moset's data was consulted by The Doctor aboard Voyager in an effort to remove a cytoplasmic lifeform that was living on Lt. B'Elanna Torres. Considering him a genius (but lacking knowledge of the atrocities he had commited), The Doctor even made a holographic simulation of Dr. Moset as "Medical Consultant Program Beta one". The Doctor deleted the hologram after the creature had been removed as he was unable to reconcile Moset's successes with the brutal methods he resorted to in order to gain the data in the first place. (VOY: "Nothing Human")
Moset was played by actor David Clennon. In the novel The Battle of Betazed, Crell Moset experiments on the Betazoids after the Dominion conquers the planet, hoping to create telepathic Jem'Hadar, only for the experiment to fail when the Jem'Hadar prove incapable of coping with the increased sensory input. Moset also appeared in the Voyager Relaunch Spirit Walk novels, where he is rescued from Starfleet capture by a renegade Changeling who became trapped in Solid form several years ago and seeks Moset's help in restoring his old abilities, simultaneously experimenting on Chakotay's people to unlock the full potential of their Sky Spirit-enhanced DNA. At the conclusion Moset is confronted by Voyager's new doctor Jarem Kaz, a Trill whose previous host's wife was killed by Moset's experiments, who coldly forced Moset to realize just how horrific and evil he would be regarded as by future generations, subsequently refusing to kill him as he preferred to leave Moset forced to look at a mirror of just how ruthless he was.
In the Star Trek: Terok Nor novel Night of the Wolves, Moset infected Kira Nerys' mother Kira Meru with the Fostossa virus in 2353 on the orders of Gul Dukat, who believed that she becoming a liability. Meru died shortly thereafter.
His mirror universe counterpart appears in the novella The Mirror-Scaled Serpent and the short story "Bitter Fruit" contained in the anthology Shards and Shadows. He is described as performing experiments similar to those conducted by his primary universe counterpart on Template:MUs and others species on behalf of the Klingon-Cardassian Alliance.