He is the malevolent personality of Bruce Banner, personifying all of Banner's resentment at the way he is treated by the world. The Devil Hulk is also one of the Hulk's enemies, constantly threatening to escape confinement in Banner's mind and destroy the world that has tormented and abused them, simultaneously leaving nothing intact that Banner holds dear.
It first appeared when Banner was dying of Lou Gehrig's Disease, Banner using a machine to travel into his mind and make a deal with the three dominant Hulks that they would gain control of his body once the disease became too much for him to bear, while leaving him able to influence them enough to stop them from doing anything he wouldn't want them to do (If he hadn't done that, every Hulk in his subconscious would have gained access to the real world when his own mind 'died'). The Devil was revealed at this point, but he only escaped a short while afterwards, when the machinations of General Ryker shattered the barriers keeping the Devil imprisoned in Bruce's psyche. Fortunately, despite the Devil's attempts to escape by trapping Bruce in an illusionary paradise, he was contained long enough for a cure for Banner's condition to be found, before finally being contained in Banner's subconscious by Banner himself, the Savage Hulk and Joe Fixit, the Professor Hulk remaining out in the real world to help scientists such as Doc Samson and Reed Richards of the Fantastic Four find a cure for the disease using a plan devised by the Leaderand samples taken from the corpse of Brian Banner.
During the Chaos War storyline, Brian Banner returns from the dead and ends up becoming a hybrid version of Guilt Hulk and Devil Hulk.
If Devil Hulk would appear in the series, he would have to be created by the Leader using both the Hulk's blood and Devil Dinosaur's blood mixing them together and perhaps injecting it into Brian Banner to evolve him into the Devil Hulk and if this were to happen, it would be in the season 1 finale or sometime later in season 2 and if that happens and as Brian Banner, the monster will be voiced by the famous voice god in LA
Frank Welker
Frank Welker has been known for voicing a huge variety of characters and providing vocal effects for animals and creatures and since he voiced Megatron for over the years since the first Transformers series of the 80's, he would definately be the voice actor to voice the Devil Hulk since Fred Tatasciore is voicing the Hulk, Welker's voice would serve suitible as that of a father like figure to Tatasciore.
To find out if that happens, stay tuned for more Hulk and the Agents of Smash episodes