The Shinma War is the great conflict fought between the ma-ō Ruby Eye Shabranigdu and the shinzoku Flare Dragon Ceifeed for dominance over the Slayers world. The war began at the same time as that world's creation. It is unknown how long this battle lasted; however, the conflict reached a conclusion in approximately 4000 BK(?). Ceifeed used his power to split Shabranigdu into 7 pieces and sealed them into various human souls. This act exhausted Ceifeed's power, causing him to sink into the Sea of Chaos.
Though the Shinma War has ended, the overall conflict between shinzoku and mazoku has not. Before sinking into the Sea of Chaos, Ceifeed left behind four parts of himself, known as the Dragon Kings: Aqualord Ragradia, Firelord Vrabazard, Airlord Valwin, and Earthlord Rangort. Furthermore, Shabranigdu at some point created five subordinates of his own: Hellmaster Fibrizo, Chaos Dragon Garv, Greater Beast Zelas Metallium, Dynast Grausherra, and Deep Sea Dolphin. The shinzoku-mazoku conflict is continued with the Dragon Lords and the ryūzoku fighting on one side, and Ruby Eye's subordinates and the lower ranking mazoku fighting on the other.
Since the end of the war, however, at least three pieces of Shabranigdu have been revived. The first such revival was the focal event of the Kōma War.
The force of power used by both Ceifeed and Shabranidgu in the war was so great, that it destroyed more than half of the original continent. When looking at a map of the Slayers world (see right), the battleground of the Shinma War is shown at the center of a large, almost perfectly circular ocean. This shape is reminiscent of a crater left by a gigantic explosion.
The battleground of the Shinma War was left permanently destabilized after the war ended. During Slayers Try (approximately 1013-1014 AK(?)) servants of the Night Dragon Vorfeed used that instability to build and open a gateway between their world and the the Slayers world. They hoped to summon Dark Star Dugradigdu, the ma-ō of their world, into the Slayers world and split his power in half, leaving one half in their world while trapping the other half in the Slayers world, making Dark Star easier to destroy.
That battleground is said to be forbidden to both the shinzoku and the mazoku of the Slayers world; however, Xelloss did not appear to have any problems with entering it during Slayers Try.