MTG Treachery

To choose some non-Leader identity cards at random, you may for example shuffle the remaining ones from outside the game in a face-down pile, then reveal the top cards of that pile. If you don’t want to shuffle all your remaining identity cards as it can be a logistical nightmare, you can also use a die roll on a small subset of cards, or any other clear and mutually agreeable method.
The Wearer of Masks’ ability to become a copy is a replacement effect. Because turning an identity face up and applying replacement effects both don’t use the stack, players won’t be able to take actions between the time you announce that you’re turning The Wearer of Masks face up and the time it has become a copy of the identity of your choice.
Any "When [this identity] is unveiled" or "As [this identity] is unveiled" abilities of the copied identity card will trigger and apply if The Wearer of Masks is unveiled.

If the copied identity card has an X in its abilities, X is 0.
The Wearer of Masks stays a Traitor. It cannot become another identity type this way.
When The Wearer of Masks is turned face down, its copy effect wears off. While it’s face down, it’s a Traitor identity card that can be turned face up for an unveil cost of {X}.