And so, Lich Week ends in flames.
"By fire be purged!"
was the Elemental Lord of Fire, and a servant of the Old Gods. He fought alongside his masters against the Titans, but he and his kin were ultimately defeated alongside the Old Gods. Ragnaros and the fire elementals were banished to the Firelands, which was intended to act as both their new home and prison, while the Titans ordered Azeroth to their liking.
Ragnaros was eventually summoned to Azeroth by the Sorcerer-Thane Thaurissan. Having had his forces routed from Grim Batol, and now facing the combined armies of the Bronzebeard and Wildhammer clans, Thaurissan was desperate for anything that would give him and his people an edge against their enemies. Using the Cipher of Damnation, Thaurissan, with the aid of his most trusted allies, summoned the Fire Lord. The sudden devastation unleashed on the Red Ridge Mountains, and the creation of Blackrock Mountain as fallout, caused the dwarven armies to pause, and turn back. They returned to their kingdoms, fortified their southern borders, and called it a day. They wanted no part in that mess.
Welcome to the City of Thaurissan! Mighty capital of the Dark Iron Dwarves and site of the summoning of Ragnaros! It's seen better days.
As for Thaurissan and the Dark Iron Dwarves, they were enslaved by Ragnaros and forced to serve him as punishment for having the audacity to summon him. As the Dark Iron Dwarves went about constructing a new home for themselves within Blackrock Mountain, Ragnaros made a home for himself and his minions within the Molten Core, hidden beyond the depths of Blackrock Moutain.
Ragnaros continued to gather his strength, however his minions soon suffered a series of setbacks. First the orcs invaded and claimed most of the mountain for themselves, driving the Dark Irons into the depths. Then, just when the orcs have been weakened enough to drive them out, the Black Dragonflight decides to make their home there and reinforces the orcs. Still, not Ragnaros' problem. He was waiting to gather enough strength to unleash a fiery apocalypse on Azeroth.
Eventually, a group of forty adventurers succeeded in storming his lair in the Molten Core, killing all his minions, and was then called forth by that bumbling idiot he'd appointed as majordomo. After killing Executus
, Ragnaros prepared to smite those forty troublesome adventurers, only to be defeated and banished back to the Firelands. He would soon have his chance for revenge, however.
"By fire be purged!"
With Deathwing's return to Azeroth, and the resulting Cataclysm, the Old Gods made their bid to end the world, once and for all. Ragnaros was quick to answer the call of his former masters, and with the aid of the Twilight's Hammer, was summoned to Azeroth once more. This time, however, upon Mount Hyjal. Tasked with burning the World Tree to the ground, Ragnaros went about his new mission with renewed enthusiasm. However, his forces were soon driven back by the Defenders of Hyjal, and he himself was banished back to the Firelands once more. The Defender of Hyjal then launched a counter attack on him and his forces within the Firelands. Despite the services of his new majordomo, Fandral Staghelm
, and the Druids of the Flame, adventurers were able to storm his fortress of Sulfuron Keep, and kill him.
Having been killed in his home plane, Ragnaros was well and truly dead.