Mass Effect/Characters

Saren Arterius is a fictional character within the series of Mass Effect video games. He serves as the primary adversary of the first game.

Background
According to the character biography posted by BioWare, Saren Arterius is a former turian Spectre known for 'getting results' by any means necessary. More often than not, this meant he killed everyone and everything in range -- the target, any witnesses, and innocent bystanders as well. In the novel Mass Effect: Revelation, he is seen torturing and killing his victims mercilessly, rarely having any regards for sapient life or the lives of anyone in his way from getting the job done, even deliberately killing innocent bystanders and witnesses (after he had extracted key information from them.) This seething hatred for humans is speculated by other characters in the novel to stem from the loss of his brother in the First Contact War.

After the events described in the novel, and before the start of the first Mass Effect video game, Saren takes command of an army of geth through the use of a mysterious artifact known as The Sovereign, an ancient ship that supposedly predates the Protheans. With a machine army at his command, he uses them to both do his bidding and oppose the efforts and actions of the player across the story of the Mass Effect video game. One of his main goals is to unleash the genocidal Artificial Intelligence upon the galaxy once again to take revenge on humanity for killing his brother during the First Contact War, and on the Council for interceding on humanity's behalf in a war that the turians were winning.

Of note is that Saren does not consider his methods harsh. In the novel, he brutally tortures a batarian until, having exhausted the information resources he provided, Saren snaps his neck while he is unconsious, considering himself to be merciful and that he isn't "a monster."

In the a trailer for Mass Effect, Saren battles Shepard with deadly force. The trailer also implies he murdered a fellow turian Spectre, Nihlus.