From the Encyclopedia of Comic Book Heroes!
An ingenious criminal mastermind and master puppeteer who plans each of his gang’s crimes in painstaking detail and then uses puppets to “enact [each] fantastic crime in miniature,” as a sort of rehearsal, so that his henchmen will know exactly what functions they are to perform during the commission of the actual crime. Maestro Dorn and his henchmen are captured by Batman and Robin in April 1952 (Det No 182: “The Human Puppets”).
So, essentially, this guy has a semi-practical, if incredibly boring, crime schtick. Got it. Someone should put him in Scarface and The Ventriliquist’s gang.
AN OBSCURE BATMAN CHARACTER. EVERY SATURDAY. THAT’S THE HIVE OF SCUM PROMISE.