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 human life or the lives of anyone in his way from getting the job done. 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 of the first Mass Effect video game, Saren takes command of an army of geth through the use of a mysterious artifact located above their planet. 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.

Saren's left arm is clearly bionic. The arm appears to be of Geth origin. This could imply that he is under the control of the Geth or he has been assimilated into their society and made into a form of leader, in a similar way to the Borg Queen from Star Trek or Cyber Controller from Dr Who. However it is also possible that the only way to control the Geth was to have Geth implants in his body. This is all purely speculative.