Canon:Chaos War

The Chaos War, also known as the Second Cataclysm, is a war in the Dragonlance setting. The war was massive, drawing in nearly all the people of Ansalon, as well as the gods themselves. The war was so devastating to the world of Krynn that it ended the current age, the Age of Despair, and began the Age of Mortals.

Background
In the early days of the universe, the younger gods, children of Chaos, whom they refer to as the Father, decided to create the world and its inhabitants. Once this world of Krynn was formed, populated with the races of humans, elves, and ogres, Chaos saw it and vowed to destroy this so-called "plaything" of his children. Hiddukel, god of trickery, convinced Chislev, goddess of the woodlands, to ask Reorx, god of the forge and the maker of the world of Krynn to create a gem which would contain a small part of Chaos. He agreed but in doing so accidentally contains the entierety of Chaos inside. He puts the newly created Graygem in the moon of Lunitari, however the gnomes retrieve it and began the chase that would later lead to morphing of their species into dwarves and kender. Eventually, the Irda, true ogres and beautiful creatures, capture it. Usha Majere, a human who had come to stay with them, according to one account, after her parents had washed up on shore after a storm, was sent away just before the unwitting Irda cracked the Graygem open, releasing Chaos and wiping out their race to every last man, woman, and child.

The Knights of Takhisis
The Knights of Takhisis, led by Lord Ariakan, son of Dragon Highlord Ariakas, initiate the release of Chaos by visiting the Irda island and accidentally scaring the Irda into releasing Chaos. However, they have more important things to tend to, so they left. The Knights of Takhisis are a dark reflection of the Knights of Solamnia, having been modeled after them.

Knights of Solamnia
The Knights of Solamnia valiantly defended themselves and their people from the Knights of Takhisis. They failed; some are killed and some are taken prisoner.

Chaos's Forces
Chaos roused a force consisting of several terrible creatures, among them shadow-wights, who could erase a person completely from the timeline, daemon warriors, nearly undefeatable soulless warriors, and fire dragons, dragons made purely of flame who were mounted by daemon warriors. This forces largest battle was in the final battle in the Abyss.

The War
The War began not against Chaos, but against the Knights of Takhisis.

The War Progresses
Palin Majere, Tasslehoff Burrfoot, and Raistlin Majere had witnessed a meeting of the gods in which it was deemed that the Dark Knights could win the war to have a united front against Chaos. Soon, they took Qualinesti and the nearby lands, however Thorbardin and Silvanesti eluded them. This was soon to be the least of their worries.

Earlier, Usha Majere had met with Reorx and he had told her to capture a drop of blood in the broken Graygem and seal it, which would force Chaos to leave Krynn least he be trapped in one form, which would be unbearable for Chaos. Palin and Raistlin had also gone away to make preparation for the battle.

Chaos Attacks
Chaos launched his attack with a wave of shadow-wights that wiped out a large contingent of Knights of Takhisis at the High Clerist's Tower. This prompts a meeting between Ariakan and Takhisis, his queen and grandmother, who blesses the Knights weapons. This done, the Queen returns to the horrible battle raging in the Abyss between Chaos and the other gods. Steel Brightblade's force of Knights had been ordered below to be held in reserve, with the plan of returning after the battle to take over the broken world. Later, Trevalin, Steel's superior and commander, goes up to inspect the battlefield. He returns and keels over, dead. Steel goes up and inspects it along with his men, and he finds everyone, including his Lord Ariakan, dead. Steel, prompted by a vision of his father, Sturm Brightblade, decides to take up the dragonlances found in the lower chambers and ride to defeat Chaos. He finds, however, that his evil nature cannot be allowed to touch the dragonlances, however a group of Solamnic Knights who had been taken prisoner arrive and offer to take up the dragonlances, and Steel agrees.

The Abyss
The Solamnic Knights and the Dark Knights ride their dragons into the Abyss. Palin Majere, who has the great Mage's spell book, joins them. Palin manages a powerful spell that blinds Chaos, in the form of a fire giant, resulting in Steel being able to wound it. He is unable to draw the blood needed and is killed by Chaos. Tasslehoff runs up to the God's foot and draws the required blood. Usha traps it in the Graygem, defeating Chaos. Unfortunately, Tasslehoff is stepped upon and killed before the God is neutralized.

The Aftermath
Chaos and his legions disappear. Only the bodies of the dead remain. They are placed in the Last Heroes Tomb in Solace, Knights of Solamnia lying side by side with Knights of Takhisis. Tanis Half-Elven is also buried on a special bier, as was Steel Brightblade. Tasslehoff Burrfoot's name was inscribed on his burial, a hoopak (the travelling stick of the Kender) placed beneath it.

The stars of the gods are replaced with new constellations, and the moons change into one single pale moon. It is revealed by Fizban, also known as Paladine, that the gods have left the world to force Chaos to withdraw. This ushers in the Age of Mortals, the last and longest age, as declared by Fizban. It should be noted that this last part has been retconned out in the War of Souls trilogy.