|“||Who is Karras, but the Hand of The Builder? What the Builder wills, Karras... does! What the Builder wants, Karras... makes! Prraaiisse to Karras! (pause) ...And the Builder...||”|
|— Karras, considering himself above The Builder|
Karras is the main antagonist in Thief II: The Metal Age and the head of the Mechanist Order. He was a brilliant inventor, sociopath, genius, and prophet who split from the Hammerite organization to found his own faction, due to extremist beliefs, namely that all organic life was inherently flawed. He also had a distaste towards the conservative, insular nature of the Hammerites and their slow technological progress. Though Karras suffered from a speech impediment, he was very charismatic and commanded a loyal army of Mechanist followers.
Before the Mechanists
Karras showed initiative during his time as a Hammerite. When a thief named Gibson attempted to steal Lord Bafford's Scepter after Garrett had already stolen it, Karras offered Bafford an unknown ransom for Gibson, rather than letting him be turned over to the City Watch. While it is unknown why he wanted Gibson, it is possible he used him as one of the early experiments for his scheme involving the Masked Servants.
When Garrett lost his eye to the Trickster, Karras was the one who designed the Mechanical Eye given to Garrett. Karras said, shortly before his death, 'I gave the eye to thee in the hopes that thou wouldst be an ally, but 'twas not to be.'
The Builder's Paradise
Karras planned to eliminate all organic life in The City, and to do so, he offered the nobility gifts, namely his inventions called Masked Servants. These servants were designed to be tireless and completely obedient, making them perfect servants. They were however in actuality vagabonds, beggars, and prostitutes converted into placid slaves via Mechanist biochemistry and bizarre masks salvaged from the destroyed city of Karath-Din. Each servant was also secretly equipped with a canister of rust gas. This gas fed on organic matter, killing it and converting it into an inert red powder that resembles rust. Although the gas dissipated under normal atmospheric conditions, the reaction also released more rust gas, allowing it to propagate if more organic matter was nearby. The rust gas released in the large gardens of The City's nobility would fuel a chain reaction that would destroy all nearby organisms. Using this method, he planned to wipe the City clean of life and create a "Builder's Paradise" in adoration of his god.
Karras distributed his servants and was nearly ready to carry out his plan when he was killed by his own creation. Viktoria and Garrett infiltrated Soulforge Cathedral and turned his inventions against him by reconfiguring the beacons that controlled the servants. In order to boost the gas's reaction rate, Viktoria spread vines throughout the Cathedral's many vents. Instead of releasing the gas on the hapless nobility and their gardens, they were gathered inside the hermetically sealed factory and unleashed their toxic burden. By the time Karras realized what was about to happen, it was already too late.
The Hammerites mention him a few times in their texts in Thief: Deadly Shadows. He and his sect are written about within a book that can be found in Caduca's chambers within the Keeper Compound.