Foulspawn

Foulspawn was one of the most diseased and disgusting of all Nurgle's Champions. It is said that he was so horrifying to behold and apporach that those who tried to fight him were incapacitated by nausea and gagged and wretched in disgust. Nurgle was deeply fond of this disgusting champion, and wound up gifting him with a change into That-Which-Must-Never-Be-Named. As is known by now, most creatures turned into unspeakable beasts perish within a few hours, as their biology is now that of a creature that should not be, or, more commonly, they're BLAM'D by their former comrades.

Foulspawn was an exception to this rule. Not only did he survive, he grew stronger and more powerful. By either favor of Nurgle or random whim of chance, Foulspawn's new, toad-like form was able to survive by consuming living creatures, an action Foulspawn accomplished usually by swallowing them whole. In time, Foulspawn grew not only in strength, but in intellect, and to this day remains the only known case of an unspeakable beast that was then ascended to daemonhood by the whim of father Nurgle.

His real-life counterpart would be Luke.