The egg, uncontaminated by WOTLK Gold Old God corruption, hatched into a whelp , which later was later named Wrathion. After the ashes of the Cataclysm were cleared the way for him to be that was left of the dragons that were black. 

Wrathion was a man who took his responsibility to defend Azeroth extremely seriously. even though his tactics proved to be in question He would do everything to avoid becoming like the father of his family, Deathwing.

As the Hour of Twilight at hand Azeroth's defense forces would need to do everything they could to prevent Deathwing in unleashing the full force that is the power of Old Gods, as their prophecy predicted all those years long ago. The Dragon Aspects were imposed on Azeroth through the Titans to stop this exact event, and now was the right time to fulfill their original purpose. 

The former Chief of War in the Horde, Thrall (a main character in World of Warcraft WOTLK Classic) was determined to infuse his Dragon Soul artifact with the essence of all five aspects to be used against Deathwing.

Because Deathwing himself was previously an Aspect of Earth, the shaman Thrall was required to temporarily assume the role of Deathwing in order for the ritual to be carried out. 

In the midst of the Wyrmrest Temple, in Dragonblight, Thrall and the other Aspects attacked Deathwing and mortally wounded the Destroyer by striking him with the same weapon that had broken his body ten thousands of years earlier. Deathwing tried to escape but was soon dragged out of buy WOTLK Classic Gold the air into the Maelstrom which was a huge swirling whirlpool that was bursting that was amidst the ocean, where powerful elements collide.