During this ancient conflict, when Ragnaros, Al'Akir, Neptulon and Therazane contended to lesser or greater extents (depending on their natures), the firelord determined to perpetuate a great betrayal. As Highlord Demitrian puts it when you present him with one of the bindings of the Windseeker, Ragnaros' lieutenants Geddon and Garr managed to trick Thunderaan, prince of air and offspring of Al'Akir, into a confrontation with Ragnaros that ended with the prince consumed almost utterly and his strength added to that of the firelord. What little remained of Thunderaan after Ragnaros defeated and absorbed him was cast into a vessel, shattered and its two equal pieces given to Geddon and Garr to watch over.
It seems that for some reason, elementals have difficulty in wholly dying. Ragnaros could not fully absorb Thunderaan's essence, perhaps due to his link to his element. As long as it endures, so too do those spirits bound to it.
How long the Elemental Sundering raged is unknown. Indeed, it may still be considered ongoing. What we do know is that fire elementals seem most hostile nowadays to those of fire rather than air, despite Ragnaros' trickery and brutal attack on Thunderaan. If Al'Akir plots revenge against the firelord, he's most subtle about it, but Neptulon and his cronies spare no effort to oppose the spirits of fire. However, fairly recent events changed the balance of power between elementals.
Ironically, it would be dwarves, descendents of the Earthen and worshippers of the Titans, who would help free one of the elemental lords from his prison in the Elemental Planes. Nearly three centuries before the First War, the Dark Iron dwarves led by Thaurissan disputed the rise of the Bronzebeard clan following the death of Modimus Anvilmar, high king of the dwarven people. At the time, all dwarves lived in Ironforge; but after Modiumus' death, the dwarves fought each other in a civil war to see which clan, Bronzebeard, Wildhammer or Dark Iron, would inherit Ironforge. In the end, the Wildhammers and Dark Irons were banished from Ironforge, held by the triumphant Bronzebeards.
The Wildhammers ultimately adapted to their loss by heading to what is today known as the Wetlands. Atop a mountain, they built the fortress of Grim Batol and settled into a life of exile with relatively little fuss, almost relieved to be out from under Ironforge's walls. But the Dark Iron clan could not forgive the loss of Ironforge or the victory of the Bronzebeards so easily, and they sulked and planned in the dark places of the Redridge Mountains, in their city named after Thaurissan himself.
Eventually, the Dark Irons mustered the forces to attack both Ironforge and Grim Batol simultaneously, as Emperor Thaurissan (as he now styled himself) feared allowing either city to come to the aid of the other. Deciding that the only possible way to victory was to crush both the Wildhammers and the Bronzebeards in one strike, he divided his forces in half and sent one army (under the command of his wife Modgud) to sack Grim Batol, while the remaining forces went with him to Ironforge itself.
However, both Thaurissan and his wife failed. Thaurissan was driven back by the Bronzebeards and only later would learn that Modgud, despite having summoned horrible shadow entities to despoil and besiege Grim Batol, had ultimately died when Khardros Wildhammer met her in combat and slew her, breaking the back of the Dark Iron forces besieging his city and sending them routed straight into the ranks of a Bronzebeard force sent to relieve Grim Batol. Possibly despondent and certainly desperate, Thaurissan in his desperation halted his forces and attempted a great magical working, perhaps even making use of the infamous Cipher of Damnation in an attempt to summon and bind some demonic entity to use against the pursuing Bronzebeard and Wildhammer forces.
What he got instead was Ragnaros himself. For the first time since the Titans banished them, one of the elemental lords walked the face of Azeroth. His coming was so destructive that the armies of Ironforge and Grim Batol, seeing it from a distance, decided to turn back rather than risk whatever disaster awaited them. It rent the mountains asunder, destroyed the city of Thaurissan and killed the unfortunate Dark Iron emperor of that name. Weakened by his incompetent summons, Ragnaros inhabited the lower depths of the volcanic caldera created by his eruption into the world and enslaved the remaining Dark Irons, who worshiped him as one of the Old Gods incarnate. While that wasn't actually the case, it didn't really matter to Ragnaros and his fire elementals why the dwarves served him. Bound to the Molten Core, unable to return to the Firelands of the elemental planes and his own Sulfuron Keep, Ragnaros was forced to make do while trying to find a means to breach the barrier between worlds again and bring forth his host of contentions elemental servants to not only allow him to return home, but to shatter Azeroth once and for all and consign all of it to feast in fires.
Unfortunately for Ragnaros, he soon found himself embroiled in war with the Black Dragonflight, even as his own Dark Iron servants managed to perfect a means to create golems powered by elemental spirits for use as an army. The Brood of Neltharion didn't oppose the firelord and his minions out of any sense of duty, even though, as the Earth Warder, the Aspect now known as Deathwing had been charged with protecting the very earth that imprisoned the Old Gods the elementals once served. Rather, they fought over control of the mountain lair itself and for dominance in the region. In the end, mortal adventures penetrated the hallowed Core itself and managed to dispatch Ragnaros.
However, as we found out before, elementals don't die easily. Apparently, Ragnaros was merely returned to the Firelands by his defeat, taking up residence in his Sulfuron Keep and brooding over his failure to take advantage of Thaurissan's botched summoning. However, even as Neptulon plotted to pit Lord Ahune against the firelord (perhaps in an attempt to weaken his ancient enemy before striking himself, even as Ragnaros himself had pitted Geddon and Garr against Thunderaan before striking the Prince of Air down), rumors were heard of a new threat to Azeroth. Deathwing himself is said to be ready to return and in the process shatter the barriers between Azeroth and the Elemental Plane.
We know that Ragnaros will apparently make his return on the slopes of Mount Hyjal, perhaps seeking to create an even grander version of his Molten Core in its depths. While it's certainly true that Ragnaros bears no love for the Black Dragonflight that helped balk his plans last time, it's not hard to imagine him taking advantage of the Cataclysm to return. The real question is, will anyone be able to stop him this time?
Next week we discuss Therazane and the earth elementals.