The One Born Dead.
There is no distinct personality trait that anybody would enjoy about Bhal'yeth.
For there to be life, there must be death...
Bhal'yeth is the afterbirth of the creation of the universe. His power fueled creation, and as such the universe came into being. For there to be life however, there must also be death. By supplying creation with the power it needed to live, Bhal'yeth's original form was reduced to a shattered husk. The negative energy of creation was pulled to this broken husk, and from the life of the universe was born Bhal'yeth, the personification of all things negative.
Bhal'yeth traveled all of creation, with no meaning to his so called life other than to destroy and kill. To rot and corrupt. In his mere presence, the dead would rise, and all things would rot and decay. He destroyed many worlds before the Old Gods decided that he was a threat.
Forging armor the seal Bhal'yeth's true deathly power from the world, the Old Gods combined their strength and imprisoned his form in the armor. To this very day he continues to roam the universe, waiting for the day that he would once again regain his former glory by shedding the armor that seals him.