The Confederacy of the Monsters was a Kingdom located within The Underground that existed from 1871 to 1875. The Confederacy was formed on the basis that the policy on Humans that fall into the Underground needed to be changed. The catalyst for this succession from the Kingdom of the Monsters was The Justice Human entering the Snowdin Forest. The defense of The Justice Human, and the goal of returning him to the Surface, was one of the main goals of the Confederacy. When the Justice Human was killed in 1872, the goal shifted to make sure another Human was not killed in the Underground ever again. When The Vengeance Human entered the Underground in 1873, he joined the Confederacy during the war. The Vengeance Human was killed in 1874 by Wing Ding Gaster during the first ever field test of the Gaster Blaster. After this event, support for the war, and the Confederacy, began waning until 1875 when the Confederacy officially surrendered to the Kingdom of the Monsters.