The Great War.The "Great War" lasted around ten years, preceded by a century of tension. Mistral had conquered Anima and made an alliance with Mantle, exchanging of supplies and technology. An "incident" in Mantle led to a decree that abolished the arts and repressed self-expression, attempting to control the citizens' emotions to reduce Grimm attacks, to which Mistral partly complied when Mantle tried to enforce the decree in other kingdoms. This and other issues, such as Mistral and Mantle's treatment of citizens or maintenance of slavery, caused conflicts with Vale's citizens, resulting in a clash when Mistral tried to expand to the east coast of Sanus. The king of Vale avoided conflict, but the opposing settlers did not, their riot sparking the first battle of the "Great War". Mantle supported Mistral, with battles starting in both Anima and Sanus. Grimm attacked all combatants, sometimes forcing cease-fires between the humans to deal with the monsters. Vacuo initially stayed neutral until Mantle and Mistral tried to force their cooperation, instead supporting Vale in fear of the other side's victory. The war ended with the "Vacuo campaign", Mistral and Mantle attempting to claim Vacuo's Dust mines and cut off supplies for their enemies. The king of Vale led his and Vacuo's forces and, armed with crown, sword and scepter, he decimated the enemy army. The "deadliest battle of the war" cost many lives and created the legend of the "Warrior King". In the end, everyone bowed to the king of Vale, who refused to rule over Remnant and established the treaty of Vytal instead; territories were redistributed, slavery abolished, and governments restructured. The last king of Vale founded the Huntsmen academies and gave his most trusted followers command over them, promising to teach mankind how to fight on the condition it was not against each other; a bargain Qrow says mankind has not honored.