Mordin Solus

"Had to be me. Someone else might have gotten it wrong."

- Mordin Solus

Mordin Solus is a Salarian Scientist first introduced in Mass Effect 2. He runs a clinic on Omega, and was one of the Salaraians that helped forge the genophage.

Personality
Mordin is described as being like a "hamster on coffee" and indeed frequently displays an irreverent, easily excitable, and jovial personality. He is easily distracted by intriguing scientific discoveries and is also prone to burying himself in his work, which he accomplishes with relish and a smile.

Past this outward image of cheerfulness however shows a somewhat more tortured and conflicted soul. Mordin's past involvement with the Genophage has left him with feelings of guilt and though Mordin if confronted maintains that the Genophage was necessary (and gives many solid arguments as to why) it is clear that he remains conflicted on the matter.

Mordin frequently shows signs of an ends-justify-the means philosophy, but not within some boundary of restraint. For one though Mordin is quite agreeable to killing those he feels are a danger to society and the well-being of others, he also refuses to kill with medicine and has never once done so, not even when being a part of the Genophage. He is also very disgusted with the desperate actions taken by his former protege to cure the Genophage, showing that he does not always believe the ends to justify the means.

As a Salarian Mordin copes with grief and other emotional issues very quickly, as Salarian lives are much too short to waste time reminiscing. But even here, closer inspection reveals that Mordin is not quite as adept at working past old ghosts as he would lead others to believe.

Mass Effect 2
In Mass Effect 2, one of the first people Commander Shepard can recruit to fight the Collectors is Mordin. He helps him clear a plague that is spreading on Omega, and then for his help he joins the team. Mordin also helps create a means by which the Normandy Crew can battle the Collectors without being immobilized by their seeker swarms.

It is later learned that Mordin helped upgrade the Krogan Genophage to keep the Krogan from overcoming it, and though he justifies his actions as being a necessary evil he clearly feels some remorse over them. When he learns that his old protege Maelon has been kidnapped by Krogans on Tuchunka, Mordin sets out to rescue him, and is again confronted with the morally grey nature of his past. Finally locating Maelon, Mordin and Shepard learn that Maelon is there by choice, and intends to cure the Genophage no matter the moral cost. Disgusted with his protege's actions, Mordin resolves to kill him, but can be talked out of it by Shepard. Shepard must also decide to tell Mordin what to do with Maelon's remaining data, and whether or not it can be used for a greater good or if it is not worth keeping.

Mass Effect 3
In Mass Effect 3 (assuming he survived the sucide mission) Mordin Solus returns helping either Urdnot Wrex or Wreav try to cure the Krogan Genophage. If Shepard chooses to help, Mordin will ultimately sacrifice himself to disperse the cure. But if Shepard chooses to sabotage the Genophage Cure, they must either kill Mordin in cold blood or convince the doctor to stand down, which they can only do if both Urdnot Wrex and Eve are both dead. If Mordin survives, he can be contacted before the final battle.