Second Dalek War

The Second Dalek War was a war between the Daleks and humanity. It was one of a series of conflicts which became known as the Dalek Wars.

Origins
The previous conflict between the Daleks and Humanity had seen the Daleks launch an attack on Earth in 2400 after the Emperor ruled it an emergency to take control of the Solar System before humanity could do so, (COMIC: Invasion of the Daleks) but this war had been won by the humans, with the Emperor forced to work out a peace treaty with them. (COMIC: Battle for the Moon) After "two hundred years" of peace, however, a mysterious Mechanical Planet came which threatened both Skaro and Earth. The Emperor landed on Earth and made an offer to eliminate the threat in exchange for the return of confiscated Dalek weaponary, which the humans grudgingly accepted. Ultimately, the Daleks destroyed the Mechanical Planet and, with their weapons and power restored, the Emperor vowed once more to conquer "all the planets in every sky." (COMIC: The Mechanical Planet)

Thus did it come to pass that in the 26th century, following the human-Draconian War, the Dalek Empire thus tried to manipulate the rival empires of Earth and Draconia into another war. The Daleks allied themselves with and supported him with Ogrons, using hypnosound technology to trick humans and Draconians alike into thinking the other empire was attacking. They also quietly conquered the planet Spiridon and began experiments to turn their armies invisible; an army of ten thousand Daleks awaited this treatment. However, the Third Doctor exposed their plan, helped General Williams and the Draconian Prince escape from the Master's custody and sent a message to the Time Lords to take him to the Dalek army. With the help of a group of Thals, the Doctor prevented the Daleks from retrieving the army. Once the Earth and Draconian Empires learned it was the Daleks disturbing the peace, war was declared on the Dalek Empire. (TV: Frontier in Space, Planet of the Daleks)

The war
The Second Dalek War was a vicious conflict that ravaged many worlds and lasted decades. One of the earliest events of the war was the First Dalek Incursion, during which the planet Arkheon was destroyed by Dalek planet splitters. The Wayfarer, a ship that would play a crucial role towards the war's end, saw action during the incursion. (PROSE: Prisoner of the Daleks)

Earth's government enacted emergency powers that allowed it to commandeer personnel, resources and ships from powerful human corporations. (PROSE: Love and War, Return of the Living Dad, Deceit) Even Earth's worst criminals were enlisted after being given the choice of execution or becoming highly armed Dalek Killer soldiers. Bounty hunters could also make a living by killing Daleks and returning their eyestalks to the Earth forces to confirm the kill. They were worth 20 decacredits. (COMIC: Abslom Daak... Dalek Killer, PROSE: Love and War, Prisoner of the Daleks)

Because the war lasted so long, there were many humans born during the time of the conflict that did not know what it was like to live in times of peace. This was referred to as the Dalek Generation. (PROSE: Prisoner of the Daleks)

The Dalek military forces upgraded from their more basic casings that they entered the war with (TV: Frontier in Space, Planet of the Daleks) to a more advanced casing. The Dalek drones and low-ranking officers were all bronze. (PROSE: Prisoner of the Daleks)

The end of the war
After decades of fighting, the Daleks came to realise that they were losing. To try and secure victory, they tried to utilise the Arkheon Threshold, a rift in time located in the remains of Arkheon, to wipe out humanity from its very beginnings. They captured human prisoners and use them as slaves to dig through the crust of the planet and reach the Threshold.

When the TARDIS jumped a time track, the Tenth Doctor found himself on the planet Hurala during the war. After capturing a Dalek prisoner, he loosely joined forces with a crew of Dalek Bounty Hunters on board the Wayfarer, a ship commanded by a Space Major who had deserted, Jon Bowman. About the same time, the people of the planet Auros learned of an approaching Dalek fleet. The population destroyed their planet with Osterhagen technology and fled before the Daleks arrived. However, it was all a trap. The Daleks waited for the refugee fleet to come to them and the Dalek Inquisitor General, Dalek X, ordered the citizens sent to work in the Arkheon mines.

The Wayfarer crew interrogated their Dalek prisoner. The Doctor extracted — he believed — the Daleks' plan to use the Arkheon Threshold to achieve victory. He did not realise the Daleks had already found the Threshold until it was too late. The crew and he were taken prisoner on Arkheon and the Doctor admitted who he was. Dalek X arrived to subject the Doctor to torture and extract Bowman's brain to learn how to bypass Earth's defence systems.

The Doctor explained that the Daleks did not have the technology to use the Threshold but Dalek X thought the Doctor's TARDIS would allow their plan to succeed. The Doctor took Dalek X to Hurala, using the TARDIS as a lure, where Bowman, Koral and he escaped due to Cuttin' Edge attacking a Dalek and being exterminated. The Doctor detonated the abandoned fueling station on Hurala, destroying all the Daleks as well as Dalek X's flagship, the Exterminator. The loss put a huge dent in the Dalek war machine. Earth pushed back their fleet and the Dalek Empire surrendered shortly after. Dalek X was knocked down a gantry and survived the explosion, though was badly damaged and unable to escape. The Doctor visited him after receiving his transmission, but said nobody else would, the Dalek Fleet was in disarray, and that he had sealed the Threshold. (PROSE: Prisoner of the Daleks)

Aftermath and legacy
For the victorious Earth Central forces, the result also led to a major restructuring of humanity's intergalactic government. The corporations, formerly masters of human colonies across explored space, had suffered as a result of the Human-Draconian War, the Dalek Plague and the harsh rule enforced on them by Earth's rulers. Advances in communications technology helped Earth occupy the vacuum left by the corporations' rule, and historians such as Galactic Federation Archivist Ven Kalik agreed the seeds of the later Earth Alliance and Earth Empire were sown in the Second Dalek War. (PROSE: Deceit)

The outbreak of the Third Dalek War some time later only worsened the burden felt by the Earth Empire after the Human-Draconian War and the Second Dalek War and their expansionist phase came to an end. Planets such as Mechanus were never colonised and the Mechonoids created to prepare these planets for colonisation were forgotten about. (PROSE: The Chase)

The Daleks returned to using their more basic casings after the war. (TV: Destiny of the Daleks, Resurrection of the Daleks et al.) However the stronger casings used towards the end of the war eventually came back into use and became standard for all Daleks during the Last Great Time War. (TV: Dalek, The Last Day, The Day of the Doctor) The New Dalek Paradigm also made use of the casing for all of their foot soldiers. (TV: Asylum of the Daleks, The Time of the Doctor, Into the Dalek, COMIC: The Dalek Project, PROSE: The Dalek Generation)