Conductor of an unnamed American City Philharmonic Orchestra from the "Musical Justice" story of comic book Daredevil Comics #104 (November 1953). His violinist and "friend" Abbe Caffa reveals to him privately that he has finished his first symphony after years of work. Smarmy Mauler finds it so good he must steal it. He sends Caffa on a month's vacation, and while he's gone, presents the work as his own and rehearses it with the orchestra. When Caffa returns, he confronts Mauler in front of the orchestra, but is disbelieved, and fired.
Series protagonists The Little Wise Guys, a bunch of kids,
His name is a parody of real composer Gustav Mahler (1860–1911).