As son of the powerful Mephisto, the demon known as Blackheart had already made a reputation of himself as powerful demon, his intellect unmatched, combined with his ruthlessness on the battlefield, and complete mastery over souls and magic. It would be no question that Blackheart would become prince of the underworld, however, over the years of his reign as prince, he had grown tired of how Mephisto operates and rules over the underworld. He viewed Mephisto ways as outdated, and ineffective. Which would lead Blackheart to attack his father.

Blackheart once tried to overthrow his father, Mephisto. He did not like how his father handled ruling the underworld, so Blackheart started to coup against Mephisto. However, he lost the fight. As punishment, Mephisto tortured him endlessly, testing his sanity, and then banished him. Mephisto would then give him his title back as second in command of the Underworld armies, which Blackheart would reluctantly agree to, and Mephisto's reasons for this is unknown. This means Blackheart was back on Mephisto's leash. However, Blackheart has been secretly founding new power and collecting souls to one day overthrow Mephisto. He tells no one of this plan.