The Architect is a powerful Darkspawn and the main antagonist of Dragon Age: The Calling as well as returning in role of a secondary antagonist in Dragon Age: Origins - Awakening, he does not appear in Dragon Age II but is mentioned in passing during the in-game dialogue.
The Architect is a unique Darkspawn in the sense that he has a much more independent outlook on life - not relying on the Old Gods or other Darkspawn traits, being capable of acting polite and calm but in reality being a cold, manipulative and malevolent being willing to sacrifice his own allies in order to ensure its plans meet success.
The goal of the Architect was to bring peace between the Darkspawn and the other races of the world, however he had no sense of right or wrong when it came to the methods by which to obtain said "peace".
Believing that the Grey Wardens were the answer to the plight of both Darkspawn and the other races the Architect began a grand scheme to give the darkspawn Grey Warden blood to attempt to prevent more blights.
- In 2nd Volume of Dragon Age: World of Thedas it's revelated that he's an ancient magister turned into the first darkspawn just like Corypheus. However he seems amnesiac.
- In novel Dragon Age: The Calling his appearance is completelly different, he's described as a hurlock in an elegant robe.