Thane Krios

Thane Krios, one of the most skilled assassins in the galaxy, was born in 2146. At the age of six, his parents gave the young drell to the hanar to be trained as an assassin, as part of the Compact between the two species. He made his first kill at twelve. He met his wife Irikah during an assassination, where she noticed the targeting laser on Thane's target and stepped in to block his shot. Thane was intrigued that a civilian would put her life on the line to save a complete stranger, and later fell in love with her. The hanar released him from his compact to let him have a family, but with no other skills, Thane freelanced his services. Eventually Irikah gave birth to their son, Kolyat, and Thane worked very hard to keep his work and his family life separate. However, some time after Kolyat was ten years old, Irikah was murdered in revenge for a batarian mercenary leader whom Thane had killed. The mercenaries paid the Shadow Broker for his identity and killed Thane's wife because they were unwilling to face Thane himself. Thane traveled back to Kahje for Irikah's funeral and left Kolyat in the care of his aunts and uncles while he hunted down his wife's killers. Thane finished the job, killing everyone involved in his wife's murder. Thane notes that while he has always striven to kill his targets as quickly and cleanly as possible, he took extra time with them. He claims these murders are the only ones where he made the decision that they should be killed, and the only time emotions have affected his actions. Commander Shepard first confronts Thane on Illium, where he had been based for the prior two years, whilst he is on a mission to assassinate Nassana Dantius. While Shepard talks with Nassana to discern the assassin's whereabouts, Thane drops from the ceiling and takes out Nassana's bodyguards before killing her with a pistol shot at point-blank range. He tells Shepard that he hoped this mission would be his last, expecting that he would have been killed by Nassana's guards. He reveals he is slowly dying of a disease which is later revealed to be Kepral's Syndrome. He joins Shepard's suicide mission against the Collectors, perhaps hoping to die in the process, which he feels will redeem him from his past evils.

Thane is unusual among drell in that he follows the old polytheistic religion of his species rather than adopting those of the hanar or asari and spends much of his time in prayer and meditation, even within his work. To find a target, he prays to Amonkira, the lord of hunters; when defending another, he prays to Arashu, goddess of motherhood and protection; after taking a life, he prays to Kalihira, goddess of oceans and the afterlife. If Shepard asks how Thane can reconcile his deep spirituality with a violent profession, he explains that the body and soul are seen as separate entities by his faith. Thane sees his body as merely a tool or vessel through which people can choose to commit an act of murder, similar to a gun. While this philosophy spiritually absolves him of his crimes, that convenience is undermined by the eidetic memory native to his species; the ability to perfectly recall every single act of murder he committed over the years has weighed down on his conscience, thus Thane cannot help but to feel regret over his actions. This guilt, combined with an impending death, compels Thane to join Shepard's campaign against the Collectors as a gesture of penance.

(Content taken from the Mass Effect wiki.)