He wears a blue hat, cape, and mask that completely hides his appearance. This type of costume is common among the 207 "Phantoms" that live in the Paris sewers.
He is vengeful but capable of forgiveness when treated properly.
He worked for the wax museum, making figures for them, until he was fired. The owners took credit for his work and sold the museum to a new owner, Cherchay La Femme.
Scooby-Doo (Archie Comics)
He set out to take revenge by hiring actors to disguise themselves as monster figures in the museum and make them "come to life." After he was caught, Cherchay offered him a job again and credit for his work, which he accepted.