Mordin Solus

Mordin Solus was a salarian geneticist, doctor, and former operative of the Special Tasks Group, the STG. Brilliant and fast-talking, he had performed reconnaissance and helped modify the krogan genophage before retiring to run a clinic on Omega, where Commander Shepard recruited him for a high-risk mission against the Collectors. A consequentialist who believed the ends could justify the means yet disliked killing without cause, Mordin spent his later years measuring the weight of what he had done to the krogan. (Mass Effect 2; Mass Effect 3)

The genophage project#

Mordin's last mission with the STG concerned the krogan genophage. He led a science team of geneticists, chemists, sociologists, and mathematicians, originally tasked only with studying krogan population growth, but the work changed when the team found the krogan were naturally overcoming the genophage. The only course they could agree on was to design and deploy a new strain that, as Mordin maintained, would hold krogan reproduction to a sustainable level and prevent a war that might end in the genocide of the species. A botched dispersal mission on Tuchanka cost him injuries to his face and the loss of his right cranial horn. (Mass Effect 2)

Mordin defended the decision as the only one available, but he found its ethics disturbing and even turned to religion in search of peace, only to be left with an unresolved crisis of faith. He returned to Tuchanka for follow-up work, insisting on seeing the damage he had caused rather than walking away, and afterward built a clinic on Omega, where he found it easier simply to heal people and dealt ruthlessly with anyone who threatened his patients. (Mass Effect 2)

Aboard the Normandy#

Shepard first met the fast-talking salarian on Omega, where he was working on a cure for a bioengineered plague of Collector origin that was ravaging a district. Once recruited, Mordin ran the tech labs aboard the Normandy SR-2, investigating Collector biology and improving the crew's equipment. He was affable and given to thinking aloud, often talking to himself, and he revealed an unexpected gift for singing, having once performed light opera. He took an interest in the crew's personal affairs, offering candid medical and romantic advice to any Commander who sought it. (Mass Effect 2)

Loyalty and Maelon#

During his service Mordin learned that his old assistant Maelon had been captured on Tuchanka, and he feared for the salarian's life should the krogan discover his role in modifying the genophage. Fighting alongside Shepard through the base of Clan Weyrloc, Mordin found the clan attempting to build their own cure through brutal experiments on captives, and discovered that Maelon was alive and had been helping them out of guilt. Mordin could be allowed to kill Maelon for his betrayal or be stopped, and his research data could be preserved or destroyed, a choice that would matter greatly in the years to come. (Mass Effect 2)

Curing the genophage#

If Mordin survived the assault on the Collector Base, he returned during the Reaper War, having rejoined the STG and serving as an inside source for Clan Urdnot. He was found on Sur'Kesh during the evacuation of the surviving fertile female krogan, and if Maelon's research had been saved, he used it to treat the female called Eve. Aboard the Normandy he commandeered the medical bay to develop a cure that would grant universal krogan immunity, settling on the salarian facility known as the Shroud as the means to disperse it across all of Tuchanka at once. (Mass Effect 3)

Asked why he had reversed his stance on the genophage, Mordin pointed to the changed situation, the Reaper invasion, and the turians' need for krogan support, and beneath that to a simple conviction that getting it right was his responsibility, since few salarian scientists understood the genophage as he did. On Tuchanka, with a Reaper guarding the Shroud and the great thresher maw Kalros summoned to bring it down, the moment of dispersal arrived. The salarian leadership had secretly asked Shepard to sabotage the cure in exchange for support, and the salarians had sabotaged the Shroud itself years earlier. (Mass Effect 3)

The ending of Mordin's account turned on Shepard's choices. If the cure went forward, Mordin insisted on finishing the work himself, declaring that he had made a mistake and could no longer hide behind statistics, and he climbed the Shroud to repair the sabotage as explosions tore through it, dying in the control room and, if he had sung for Shepard before, dying with a song. If Shepard chose instead to stop him, he was shot before he could reach the controls. In a narrower set of circumstances he could be convinced to vanish and let the cure fail, surviving in hiding while the galaxy believed him dead. However his story ended, those who knew him remembered a scientist who would not let the galaxy get the matter wrong, and his name was honored on the Normandy's memorial wall when he fell. (Mass Effect 3)