Mordin Solus is a salarian geneticist, professor, and a former operative of the Special Tasks Group, where he performed reconnaissance and participated in the modification of the genophage. He is recruited by General Jack O'Neill to assist in a high-risk mission against the Replicators. Mordin has a moral character best described as consequentialistic, believing the ends justify the means, though he dislikes taking life without good cause. His actions are often guided by an impersonal logic, refusing to let his conscience, personal, and emotional connections cloud his judgment of what he believes is truly best in the big picture. Though he is affable, quick-talking and friendly, Mordin bears physical scars of his time in the STG and is still handling the consequences of his past.