The Constructors of Destiny developed a computer built into the very universe to find the ultimate truth. Despite the protests of a Time Lord from the future and the Xeraphin, the Constructors of Destiny built the Great Attractor. After it was activated, its mind snapped and it annihilated its creators. It built an army using Block Transfer Computations. The army went out to gather the knowledge that could turn the Mad Mind into a god. The Mad Mind took over all the robotic races almost immediately.
The living races in the universe banded together in order to defeat this army. Their army, made of over a thousand fleets from as many planets, started the Millennium War of 150 million BC, lasting over a thousand years. The first move was made when the Mad Mind attempted to use a dark matter cloud in the Rift of Perseus but was stopped by the Dæmons.
The Mad Mind tried to create a wormhole in the Horsehead Nebula, which would have killed quintillions, but were stopped by the Osirans. A thousand of the Mad Mind's fleets were destroyed when the Euterpians and Greld, using the battle shroud of the Semquess and wielding the Omnethoth, destroyed the galaxy containing the fleets. The Mad Mind ravaged Kastria and destroyed the Kastrian fleet when the Mad Mind turned their computers against them. The Exxilons joined forces with the Uxarieans to destroy the fleets in the Andromeda Galaxy. They were caught in a trap that led to their eventual downfall and the destruction of the Crab Nebula.
A Mad Mind drone factory was attacked in a pincer movement by the Sontaran fleet and the Rutan Host. They failed and their entire army was blasted into a black hole within seconds. The Grey Hegemony and the Influence of Light attempted a psychic attack on the Mad Mind, but they were both mentally damaged in the attack. The Time Lords, led by Rassilon, eventually ignored their non-intervention policy and joined the fight. The Masksmakers of the Pageant, the Faction Paradox and the Ministers of Grace also came from the future to help the war effort.
The final event in the war was fought against the Mad Mind itself. The Nimons, with support from the Osirans, dropped ten million quantum collapsars into the Mad Mind. While the Mad Mind was breached, the Time Lords caught it in a time loop, being forced to repeat the same nanoseconds over and over again.
The gigantic computer was left inactive and sealed off by the time loop until the Quantum Archangel crisis, when the Archangel, a potent entity capable of time manipulation, broke the time loop and enslaved the Mad Mind for its personal computational system, enabling her to calculate the trillions of necessary possibilities to grant everyone and everything in the Universe a perfect life.
However, Kronos and the Sixth Doctor took out the Mad Mind by forcing it to focus its power and attacking the back door programme the Constructors never used, causing an epileptic seizure in the vast computer. Robbed of Bophemeral's power, the Quantum Archangel was soon defeated. (PROSE: The Quantum Archangel)