Elemental War The Elemental War was the destructive conflict between the forces of the Old Gods , led by Deathwing the Destroyer , and the peoples of Azeroth ( i . e . , the Horde , the Alliance , and neutral forces such as the dragonflights ) . After Deathwing ' s emergence from Deepholm caused the second sundering of the planet , there was renewed war between the Horde and the Alliance . Background . With the destruction of the Demon Soul at the Battle of Grim Batol , Deathwing fled to the Elemental Plane of Deepholm to recover and prepare for his return to Azeroth . During his absence , his son Nefarian attempted to create a powerful dragonflight , with only partial sucess before his defeat in Blackrock Spire . Sometime later , Sintharia created the powerful Twilight dragonflight . By the time the Alliance and Horde set sail for Northrend , the black dragonflight ended its battle against Ragnaros , ultimately allying with the Firelord and Ala ' kir the Windlord . By the end of the war against the Lich King , Deathwing had completely recovered from his defeat . Shortly after the heroes of Northrend returned home , Deathwing prepared for his return , sending earthquakes and shockwaves cross the planet . Allying with Deathwing , the cultists of the Twilight Hammer began spreading word of doom and destruction among the races of Azeroth , leading up to an attack of major cities by various elementals . Though these attacks were stopped , Deathwing himself finally emerged from the Maelstrom , destroying the World Pillar in Deepholm and causing the Second Sundering . The Cataclysm . The Cataclysm caused by Deathwing ' s return reshaped the face of much of Azeroth . Entire areas were devastated , resources were lost , and raging elementals attacked en masse . The upheaval caused the Horde and Alliance to fight each other for resources , while also battling the members of the Twilight Hammer wherever they could . Hyjal and Vashj ' ir . While massive resources were spent on war against their rival , both the Horde and the Alliance eventually turned their focus to the Twilight Hammer and Deathwing , directing forces to battle them on Mount Hyjal . At some point prior to the Cataclysm , Malfurion Stormrage finally awoke from the Emerald Dream . He led the Cenarion Circle against the Twilight Hammer at Mount Hyjal . Ragnaros , after being banished within the Molten Core , was summoned to Azeroth by Deathwing to destroy the World Tree of Nordrassil . Ysera , who herself was awake and active in the campaign against the Twilight Hammer , sent adventurers to awaken other Ancients to aid in the battle . At the same time , an island appeared off the coast of Stormwind , which was vital to both the Alliance and the Horde in their ongoing conflict . En route to the island , however , both factions ' ships were attacked by naga . Eventually , it ' s learned that the naga , allied with Deathwing , were waging a war against Neptulon the Tidehunter in an effort to take control of the seas themselves . Rather than allowing the naga to take control of a powerful domain , the mortal races aided the Tidehunter and thwarted the naga ' s ambitions . Repairing the World Pillar . The Cataclysm brought Azeroth closer to the Elemental Planes than it had ever been . The shaman of the Earthen Ring , feeling the distress of the planet , worked to repair the damage Deathwing caused . Thrall gave the title of Warchief of the Horde to Garrosh Hellscream while he tried to stabilize the rift within the Maelstrom , saving Azeroth from collapsing into Deepholm . Forces of the Horde and Alliance joined forces with the Earthen Ring to repair the World Pillar , but had to battle the Twilight Hammer in Deepholm to recover its missing pieces . Rather than join Ragnaros and Al ' akir , Therazane the Stonemother chose to side with the mortals , to prevent her enemies from taking her realm .