"I don't think I need to tell you that Drakkisath is not to be taken lightly. I let the thousands dead by his hand do the talking."
Following the defeat of the Orcish Horde at the end of the Second War, the Dark Iron dwarves thought they finally had a chance to take back control of Blackrock Spire. The remaining orcs were weak and lethargic, it'd be a simple task to drive them out and reclaim the upper levels of their mighty mountain fortress. Much to their dismay, the black dragon, Nefarian, thought that the upper reaches of the mountain would make for a fantastic new home for himself. By the time they were ready to act, Nefarian had already staked out his new laboratory, intimidated/recruited the remnants of the Old Horde into his army, tastefully redecorated the place, and were already mustering forces to drive them out of their own mountain.
Leading these efforts was
Lord Valthalak, a powerful drakonid warlock, except he was killed by adventurers. His successor,
General Drakkisath, a powerful dragonspawn warrior, was quick to prove himself a worthy replacement, and converted his former commander's rooms into a kennel for their new captured corehound watchdog. While his master was busy creating new abominations of magic and science, Drakkisath waged war against the Dark Irons. Soon, his forces were poised to drive the Dark Irons out of Blackrock Mountain, and destroy their master, Ragnaros. However, in a fortunate stroke of luck, the Dark Iron nation suffered a series of blows at the hands of adventurers that effectively crippled them, making Drakkisath's own plans somewhat moot. First, a hit squad of adventurers sent by King Magni Bronzebeard to "rescue" his daughter attempted to infiltrate Shadowforge City, which resulted in the assassination of the Dark Iron Emperor, Emperor Thaurissan. Following that, a group of forty adventurers assaulted Ragnaros in his lair, the Molten Core, and destroyed him, banishing him back to the Firelands. These two events effectively crippled the Dark Iron resistance, and accomplished all of Drakkisath's goals. Naturally, this meant something terrible was going to happen.
Turned out that hit-squad of adventurers who tried to "rescue" Moira Bronzebeard from Emperor Thaurissan's "vile clutches" had managed to rescue a captured human marshal that the Dark Irons were holding captive before they assassinated the emperor. Turned out that marshal had found evidence revealing that the Black Dragonflight had secretly been controlling the government of Stormwind. In one fell swoop, this explained both the presence of a black dragon on all of Stormwind's coinage, as well as just about every ill that had befallen the kingdom in recent years. Except for the loss of Kurzen's Expedition, they had nothing to do with that. While Stormwind's ire was mostly focused on Nefarian's sister, Onyxia, it turned out that Drakkisath's blood could serve as the key ingredient in the creation of the Drakefire Amulet, a magical amulet that would allow adventures entry into Onyxia's lair. General Drakkisath was killed by adventurers, but his blood still flows in the Drakefire Amulet.
In time, his master was defeated and killed, and then relocated his operations deeper into Blackrock Mountain, abandoning the upper reaches. More recently, Upper Blackrock Spire has become a base for the Ironmarch, the Iron Horde's expeditionary force into Azeroth. As a result, General Drakkisath has been removed from the game, and his effective replacement, is much more interested in dropping a giant bomb into the heart of Blackrock Mountain than sitting in his old throne room.