An untangler or disentangler is an agent who works in the Department of Implausible Crossovers. They have that title because they tend to spend their time picking various people and things out of one canon and putting them back in the one where they belong, thus "untangling" the two worlds. They do occasionally have to deal with Mary Sues, character replacements, and possessed canons, too, so most untanglers at least know how not to kill themselves with a weapon and perform a basic exorcism.