Wolfgang's parents were adventurers who fought against all manner of evil creatures in their past. It was they, along with their friends, that saved Impiltur from it's doom at the hands of the demonic forces of evil. Damian Volos and Wolfos Volos were human adventurers who fell in love after obtaining peace for their homelands. The others who fought alongside them were Xaphan Lothar and Claudia Galfien; both powerful in their own right and just as dedicated as Wolfgang's parents. It was always thought that Xaphan and Claudia would end up together, but it never came to pass. Xaphan changed. Without warning he betrayed his friends, killing Claudia in cold blood and damning Damian and Wolfos. It shamed Damian that he couldn't avenge Claudia's death and it killed Wolfos inside that the woman who was like a sister to her was gone forever.
Xaphan escaped with his life, retreating to the protection of his dark masters. If it wasn't for Wolfos being with child, they would have hunted the bastard to the ninth circle of hell. Little did they know that Xaphan's treachery went much deeper than simple murder. When the child was born they could see the signs of corruption. Horns upon his brow, a long leathery tail, fiery red hair, and darkened skin with patches of scales. Their son was born a tiefling, known by the Impilturians as 'the tainted'.
Wolfgang's life was harsh. Growing up children would avoid him, unless they had some crackpot plan to steal treats or break into an old abandoned house... then they'd invite him to their plots only to lay the blame on 'the tainted' when the adults caught them. He was never fully accepted. Tolerated for a time perhaps, but never actually treated like an equal. He learned to harden himself, to focus on his training with his father or the odd jobs he could get as a young adult before going out on his own.
Little that Wolfgang knows, his curse is not only of his blood but of his soul. The one who becomes closest to him is doomed to be consumed by a demon lord. The same demon lord with which Xaphan made a pact. In exchange for the death of Claudia, the one prophesied to be the downfall of the demon lord, and the corruption of the Volos's child he would gain eternal life and power beyond any mortal. This demon lord would wait until Wolfgang's soul would meet it's soul mate and then he would consume that poor soul, innocent or otherwise. The torment of this would surely drive the young tiefling to embrace his the dark nature of his blood and start the transformation of Wolfgang into a demon lord.