now i got the true story, here it is:
"The combined armies of Ironforge and Grim Batol then turned south, intent on destroying Thaurissan and his Dark Irons once and for all. They had not gone far when Thaurissan's fury resulted in a spell of cataclysmic proportions. Seeking to summon a supernatural minion that would ensure his victory, Thaurissan called upon the ancient powers sleeping beneath the world. To his shock, and ultimately his doom, the creature that emerged was more terrible than any nightmare he could have imagined.
Ragnaros the Firelord, immortal lord of all fire elementals, had been banished by the Titans when the world was young. Now, freed by Thaurissan's call, Ragnaros erupted into being once again. Ragnaros' apocalyptic rebirth into Azeroth shattered the Redridge Mountains and created a raging volcano at the center of the devastation. The volcano, known as Blackrock Spire, was bordered by the Searing Gorge to the north and the Burning Steppes to the south. Though Thaurissan was killed by the forces he had unleashed, his surviving brethren were ultimately enslaved by Ragnaros and his elementals. They remain within the Spire to this day."