The Hellfire Siblings are known as two of the most powerful and destructive demons in the world and there is a reason for this. Unlike most demons, Alastair and Charlie were once mortal and the siblings became known as the most dangerous pair of mortals in the entire world. Their atrocities were so terrible that they drew the attention of even the gods and after their death, the Hellfire family was banished to Shiric-Drac. However, the gods had underestimated the darkness that the siblings possessed, and once in hell the dark magic that should have consumed their minds instead granted them immense power. That kind of power had never been seen before and it drew the attention of the Demon King; Lucifer saw an opportunity and he traveled from Nagarais with the Seven Deadly Sins to Shiric-Drac (no small feat as the Fire Demons pay fealty to none) He offered the pair a place at his side and they accepted. Everybody has an origin story, However, and this Psychopath along with his Sociopathic older sister possess one of the most interesting origins I've ever seen.