Fantômas was introduced a few years after Arsène Lupin, another well-known thief. But whereas Lupin draws the line at murder, Fantômas has no such qualms and is shown as a sociopath who enjoys killing in a sadistic fashion.
He is totally ruthless, gives no mercy, and is loyal to none, not even his own children. He is a master of disguise, always appearing under an assumed identity, often that of a person whom he has murdered. Fantômas makes use of bizarre and improbable techniques in his crimes, such as plague-infested rats, giant snakes, and rooms that fill with sand.
Messengers of Evil begins when “. . . Baroness de Vibray, well known in the Parisian world and among artists, whose generous patroness she was, has been found dead in the studio of the ceramic painter, Jacques Dollon.” It ends with Fantomas' escape once again, and with Juve receiving a humiliating rebuke from the supreme head of the police detective department. But the chase has not ended.
(Introduction by Wikipedia and Don Jenkins)