Fluctlight
The digitised human soul at the heart of the Underworld project.
A Fluctlight is the soul-like core of a mind in the Alicization story. The Underworld was built to produce bottom-up artificial intelligence by raising large numbers of artificial Fluctlights, with the aim of advancing Japan's military capability.
Lore & Background
Fluctlights can be destroyed: a cruel nobleman dies when his Fluctlight fails during a clash over the Taboo Index with Kirito and Eugeo, and Gabriel dies when Kirito overloads his. Alice's Fluctlight cube becomes a prize, sought by Gabriel on behalf of the National Security Agency, while Kikuoka fakes his death and plans to protect her by getting people to keep interacting with artificial Fluctlights.
More in Lore & History
Elsewhere in Sword Art Online
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