Dorbon was not created by Morgroth he was a Valar that had been an ally of Morgroth. The other Valar tourted him into telling him everything of Morgroth. After they tourted him beyond repair they wiped his memory of being a Valar and disfigured him to look like an orc. After he was disfigured he wore a suit of armor that hid his face. It was a long time before Morgroth realised that the orc was Dorbon the Valar.