Centuries of murder in a locale named Christ's Crown, New York, draws the attention of a demon-lord, Mephisto, who creates a "son", Blackheart, from the energy of the accumulated evil.
As a demon of pure evil and murdering as well his methods and back story being too inappropriate and disturbingly violent, Blackheart was not used in any of the cartoons throughout the decades since he appeared in the comics in 1989, but in the new Hulk series, the shows creators might give the sinister villain a try for Hulk and his team to take on but it is very much likely that from now Blackheart won't be appearing in the show this year but maybe next year in 2014 and if he does he is very much expected to be voiced by the famous horror movie actor
Tony Todd
Since Blackheart is a demon composed of accumilated evil, Todd would have the right kind of accent to make the character's voice in the series very effective for fans to listen to and with Blackheart debuting onscreen in animation for the first time he'll be able to show us what he is specifically capable of in combat and because the Hulks are often called monsters on their first time teaming up together, it would be an amazing fight between monsters of different boundaries.
Until that happens we might as well wait for Marvel Animators to confirm him