Molten Core

The Molten Core is the lowest level of Blackrock Depths, inside Blackrock Mountain between the Searing Gorge and the Burning Steppes. Its caverns run with rivers, lakes and falls of lava. Ragnaros the Firelord sleeps in a burning lake that serves as a rift to the plane of fire, letting his elementals pass into the world. His servants say he once fought for the Old Gods against the Titans, who banished him and his kin to the Elemental Plane.

About three hundred years ago, during the dwarven civil war, the Dark Iron leader Thaurissan summoned Ragnaros into the world as a weapon against the Bronzebeard and Wildhammer clans. The Firelord's arrival scorched the surrounding land and formed the volcanic Core, where he has slept ever since. The Dark Iron capital in Blackrock Depths became the seat of his power, and his elementals are believed to command the dwarves.

Cut off from his home plane, Ragnaros is a shadow of his full strength and cannot stray far from the Core. Only his chief servant, the flamewaker Majordomo Executus, can wake him, and his lieutenants Lucifron, Magmadar, Gehennas, Garr, Baron Geddon, Shazzrah, Sulfuron Harbinger and Golemagg the Incinerator hold the caverns. Through the Dark Iron dwarves he is building an army of golems to take all of Blackrock Mountain, and he means to crush Nefarian and the black dragonflight, who hold the Spire above.

Duke Hydraxis of the Hydraxian Waterlords, a water elemental on an island off Azshara, recruits mortals for his war against the forces of fire. He sends them into the Core to prove themselves against its elementals, then to bring back the hands of the flamewaker captains Lucifron, Gehennas, Shazzrah and Sulfuron Harbinger. His reward, Aqual Quintessence, douses the runes near the bosses, and once every rune is doused, Executus appears and, when beaten, summons Ragnaros. Lothos Riftwaker, near the Blackrock Depths entrance, attunes raiders to a shortcut portal into the Core in return for a Core Fragment.

Garr and Baron Geddon each carry half of the Bindings of the Windseeker, which hold what remains of the air elemental Prince Thunderaan after Ragnaros tried to consume him. Highlord Demitrian in Silithus uses both halves and the Firelord's essence to free Thunderaan, whose defeat yields the sword Thunderfury. Ragnaros can also drop the Eye of Sulfuras, which, combined with a Sulfuron Hammer, recreates his weapon, Sulfuras. When Executus summons him, Ragnaros rages at being woken too early and kills his majordomo for failing him.