"He's a good engineer, despite that missing hand. But zailors fall silent when he passes."
The Genial Magician lost his job after losing his hand to a Fingerking, and he's sworn revenge on said serpent. Despite this handicap, he is still able to perform some genuinely magical magic tricks, albeit with certain preparations.
It has recently been revealed that before he lost his hand, he made a deal with the Fingerkings. He was assigned to deliver a box to someone at the Department of Menace Eradication in Watchmaker's Hill, and this individual would tell him the secret to one of the illusionist Monsieur Pleat's tricks. But the Magician betrayed the snakes and told the official who the box was from. Evidently, the Fingerkings were not pleased. (This may very well be how the Magician lost his hand.)