Of course, not everyone was immediately convinced of Dümbar's powers. Amongst the mob of bearded loonies that first sought out Dümbar's shabby hovel was one Helmut Blaueflasche, an especially unhinged militia veteran prone to conspiracy theories and occasional moments of terrifying clarity. Helmut had a few questions for Dümbar; like why, if he had indeed predicted the arrival of a city-flattening meteorite, had he not fled to safety beforehand? And also, where was his goddamn money?
Helmut would never find out. As Dümbar stood before the mob proclaiming himself to be a great prophet and doomseer, Helmut got as far as "Yeah, but hang on a minute..." when he was cut short by the skull mace that Dümbar was waving about above his head. To the surprise of everyone (most especially Dümbar himself), the skull atop the mace began shrieking in some ancient northern tongue. The empty sockets of the skull began to glow with an eerie green fire, and as the shrieking became more agitated bolts of fire shot the eyes of the skull and struck Helmut, consuming him in flame and smoke.
The mob fell silent. The silence gave way to gasps of horror and astonishment as the smoke cleared, revealing that rather than being destroyed by the baleful green fire Helmut had been transformed into a hideous fly-headed mutant. Clearly the Great Prophet FaDoom was also a mighty sorcerer...
Dümbar found this more than a little alarming, but figured it was best to play along if he was to convince the rest of the lunatics of his arcane credentials. He has subsequently attempted, on numerous occasions, to rid himself of the terrifying skull mace; but somehow it always seems to find its way back to his side. He can't understand any of the skull's demented shrieking, but it frequently seems quite irate; and the only solution seems to be to point it towards someone or something, at which point something terrible involving green fire happens and the shrieking turns to more of an insane cackling. Dümbar is fairly certain that the skull mace wants him dead.
As for Helmut, he is able to understand the skull's ranting perfectly well; but since his mouth has been transformed into a hideous proboscis he is unable to share this knowledge with anyone else. Therefore it is for reasons known only to Helmut himself that he sticks around. Dümbar is fairly certain that Helmut wants him dead.