Deathwing will finally appear in Cataclysm as announced at BlizzCon 2009, and will be the final boss encounter of the expansion. This marks his formal debut in World of Warcraft's present time. During the lore panel at BlizzCon, Chris Metzen explained the circumstances behind his corruption and the part he plays in the coming earth-shattering changes to Azeroth:
"And what has happened in recent years is that the whispers of the Old Gods have gotten worse, the power of the Old Gods has seen rising with C'thun and Yogg-Saron, there are more, their power has magnified Deathwing's power, you know, tenfold.
The gist of this is that Deathwing is seriously bad ass. In a big way.
"What has happened to spark the Cataclysm is that Deathwing, with his bachelor pad in the plane of earth that we call Deepholm...Deathwing has awoken from his slumber and literally erupted into the world. And he is so powerful that his literal explosion into the physical plane of Azeroth is what has caused the Cataclysm - tidal waves, massive volcanic eruptions at a global level....tsunamis, freak storms. No part of the world has been left untouched.
His work with the twilight dragonflight will also be expanded upon in the Twilight Highlands that surround Grim Batol.
Deathwing will be the last Dragon Aspect to finally appear in dragon form in the game, and the second that can be fought by players (the first being Malygos).
While Deathwing was once a benevolent entity, he is now completely evil. He hates all mortal races, and wishes to kill them all. He's also utterly insane, most notably shown when he had the Demon Soul. Deathwing was attached to it, such that even when warned by the goblin alchemists who made his armor that the Demon Soul's energies would kill him if he kept it with him too long, it wasn't enough for him to let go of it, and was only willing to part with, temporarily, when reminded that it would likely be stolen from him if he was dead.
In spite of his insanity, Deathwing does display a degree of cunning. Although he hates mortals, he is apparently willing to tolerate them if it can prove of any help in his plans, though inevitably he will do away with them when they have outlived their usefulness.
Despite Deathwing's overall loathing of mortals, he has respect for, and perhaps even a fear of, Medivh, stating in Day of the Dragon, that he would never willingly face Medivh in combat, though this might technically be fear of the portion of Sargeras locked inside Medivh.
Deathwing is a terrifying opponent who is as cruel as he is vicious. He cares nothing for honor or nobility, striking with whatever weapons and cunning he has at his disposal, reveling in causing earthquakes and ripping open volcanic fissures. He often sends his minions into combat while he surveys the battlefield, striking at whatever weaknesses he discovers.
Names and title
Lore from Blizzcon 2009 re: Deathwing...
Ingame model of deathwing taken from Cataclysm Friends and Family Alpha!
Current build "Internal Alpha 220.127.116.1127"
You might need a bigger sword to take this dude down..