The Mirror of Opposition is a full-length, fairly plain looking mirror. Upon gazing into the mirror the user will see them self reflected with an exact copy of them self standing directly behind them. It is not clear if their copy comes into existence after gazing into the mirror, or after looking away, but in either case the phantom they see in the mirror becomes real. Immediately upon creation their copy will attempt to kill and replace the original user.
There is as of yet no known way to differentiate between the copy and the original.