WARNING: This section or article may contain spoilers!
It is indicated that the Corruption and the Darkness are one and the same; if so, then the Darkness, like the Corruption, has its roots in the history of the first Archon and Hero, William Black. When William Black entered the Void to claim the Sword of Aeons, he was afflicted with a plague that began to waste his body away. It is revealed in Fable: The Journey that many years after William Black defeated the Court and founded the Old Kingdom, he returned to the Void and cast away the plague, which formed into the Corruption and the Darkness.
The Darkness is an extremely dangerous entity that instantly kills or destroys anything that it touches, only weakened by the light that it can consume. As Theresa explains at the end of Fable III, a world consumed by the Darkness would be devoid of colour and devoid of life. Although intelligent, the Darkness cannot be reasoned or bartered with, which makes its single-minded resolve to consume Albion that much more frightening.
The Darkness completely destroyed all vestiges of civilization in Aurora, save for the once-thriving City of Aurora. It is because of the threat posed by the Darkness that Logan became a tyrant in an effort to collect enough gold to fight off the Darkness and save Albion. After the revolution, this duty falls to Logan's younger sibling, the Hero of Brightwall. The new Hero King/Queen can only save Albion from the Darkness by either breaking his/her promises and becoming a tyrant like Logan for the greater good or by donating a great sum of gold from their personal treasury to the Royal Treasury. Failure to do so results in 6,500,000 civilians being massacred, which further results in a very empty and desolate Albion for the player to explore after completing the game.
Although the Hero of Brightwall canonically defeated the Darkness, it returns in Samarkand ten years later in Fable: Edge of the World, ultimately defeating Albion's last, greatest Hero and imprisoning him. This paves the way for the Corruptor to take over Albion, and forces Theresa to rely on an ordinary Dweller, Gabriel, to save Albion from its impending doom.
- The Darkness can become creatures called shadows (a.k.a. The Children.) They are dark, transparent ghost-like beings that attack with low health and power, but make up for this in large swarms.
- The Darkness can also inhabit statues and suits of armour and use those to attack people. These become sentinels and dark minions respectively.
- In an interview with Ted Timmins, it has been revealed that the Darkness is just one form of the Corruption, the antagonistic entity in the upcoming game Fable: The Journey.
- When first landing on Aurora, Jasper is not present in the Sanctuary, books are scattered everywhere, and as the Hero of Brightwall continues through the temple, Darkness begins to drip from the walls and ceilings. This also occurs during the battle at the end of the main quest-line.