[Acid Reign]

Hostiliar the Dragon : Dragon of Deceit
Located in the mountains of Kilaronn, compelled to stay deep in the mountain range with it's soulstone, Annihilus.

Baal came across the dragon during his campaign in Diablo II, and thought that relocating the Annihilus stone would drive Hostiliar into a horrendous rage during his search for it, thus destroying humanity in its way. Baal fought the dragon and pulled the stone from his head. Baal sent his messenger to deliver it into the west, across the western continent, intending for complete destruction of the western world. As the stone got near Tristram, Diablo's past energies saturated the Annihilus, and therefore "Diablo Walks the Earth", taking over the soul of who carried it. As the Hero defeated the mysterious Diablo, the Hero collected Annihilus and basked in it's powers, unknowing of its purpose and origin.

In Diablo III, the Hero from Diablo II (your character) is slain early in the game and Hostiliar regains control of Annihilus. One of the very first quests of Act 1 in Diablo III (or perhaps the final quest of act 1), your new hero must travel to Tristram and destroy the evil dragon once and for all.

I just realized this would probably suck. ~ end