Born of a demon father and human mother, Daimon Hellstrom possesses supernatural powers unknown to him, as well as the mysterious marking so of the pentagram. When his mother is driven mad and his sister, Satana, is lured to into the service of her father, Hellstrom travels to hell to battle "Satan". Unable to defeat him, he nonetheless steals his father's demonic trident and fiery chariot. He also discovers his own powers, emanating from the "dark soul" he inherited from his father.
Hellstrom battles Satan's demonic forces on Earth, using the powers of Hell against itself. However, he continually struggles against the evil influence of his heritage. He joins the Defenders and soons marries Hellcat. Later, Hellstrom has his "dark soul" taken from him. Weakened and in human form, he nonetheless continues to battle evil as a supernatural investigator with Hellcat at his side. Gradually, he begins to die without his "dark soul". Hellcat asks for Satan's help, and Hellstrom's father returns the source of his power. However, Hellcat is driven mad by what she sees and soon dies. Ultimately, Hellstrom returns to Hell and kills his father, taking possession of his demonic realm. Here he seeks to maintain balance between his own sense of justice and the powers of the other demon lords, such as Mephisto, Dormammu, and Satannish.