First Dark Elf Conflict

The Dark Elf conflict is a conflict that lasted for thousands of years. Dating back to 2987 B.C., the crisis was instigated when Malekith, the insane, genocidal leader of the Dark Elves, attempted to use the Infinity Stone known as the Aether to eradicate the Nine Realms. The Dark Elves were defeated and nearly exterminated by an opposing army of Asgardians led by the then-king Bor, and Malekith and several others of his species went into hibernation and until the next Convergence.

The War on Svartalfheim
In 2987 B.C., the Convergence took place, opening various portals that connected each of the Nine Realms. Malekith, a sorcerer and leader of the Dark Elves from Svartalfheim, attempted to use the Convergence as a means of spreading the Aether. The Aether was one of the six Infinity Stones, possessing the power to convert matter into dark matter; if used at full potential, the Aether could cause the destruction of an entire planet. The Dark Elves came dangerously close to using it to simultaneously destroy the Nine Realms under the belief that they could recreate it in their own image.

Fortunately, Bor, who was Asgard's king at the time, found out about Malekith's plan and led an army of Asgardian warriors to Svartalfheim, and a major battle ensued. While the Dark Elves proved to be worthy foes, the Asgardians were able to push back the Dark Elves, annihilating a good portion of their forces until only a handful of soldiers were left. Malekith then decided that it was a perfect time to unleash the Aether on the Nine Realms, but just before he was going to darken the Realms, a portal made by the Bifrost Bridge took it from him. Seeing that they now did not stand a chance of winning the battle, Malekith made his armies ships fall from the sky and kill everyone on the battleground, including his own men. By the end of the battle, it was presumed that the Dark Elves were driven extinct by the battle, and Bor placed the Aether in a secluded area so that no one would ever find it again. Unknown to him, Malekith was actually alive, having fled the battle with his servant Algrim and various other remaining Dark Elf warriors. The Dark Elves placed themselves in stasis to await the day where the Aether would reveal itself, and they could put their plans into effect once again.