Null Mages are gifted in each of the four elements. While no human could hope to reach the pinnacle of power that a Dweghom Sorcerer could muster, it is a known truism that it is easier to destroy than create. Given his access to all of the elements it is almost trivially easy for a Null Mage to dispel the efforts of even the most powerful mage, allowing the Hunter Cadre that hired him to finish the job safely and efficiently.