The Doppelganger 
Neutral Killer
Mutable Anatomy (Passive) - Immune to death at night, poison and bleeding.
Unstoppable (Passive) - Immune to most occupation and redirection abilities.
Disguise Self (Day) - You will appear as the chosen class to Investigative abilities. Cannot choose King. Lasts until a new class is chosen. - Infinite uses
Worst Nightmare (Night) - Attack a player. If your current Disguise Self class is the same as the class of the player, this attack bypasses night immunity and cannot be healed or delayed. Otherwise it is treated like a normal attack. - Infinite uses
Mass Confusion (Night) - Cause all players targeting you to target different players instead, chosen at random. Bypasses redirection immunity. - 2 uses
Must kill all members of main factions in order to win.
Example of Disguise Self Usage: The Doppelganger chooses Sheriff as his Disguise Self class. An Observer using Follow on The Doppelganger will obtain the correct information as usual, but if the Observer used Window Peek, The Doppelganger would appear to be a member of the Blue Dragon. If Worst Nightmare is used on a Sheriff, it will bypass night immunity and cannot be healed or delayed. Otherwise it is treated like a normal attack. This lasts until The Doppelganger chooses a different class with Disguise Self.
One of the most challenging parts of playing Neutral Killers is coming up with believable logs. Non Killer/Offensive claims can easily be debunked by a Princess, most Knight claims are already suspicous, and most other claims can be un-done by Observers, Alchemists and Maids. Disguise Self enables a wider variety of seemingly valid class claims while Mass Confusion can arouse suspicion with unverified target changes or just getting other players killed. In return for these greater deceptive abilities, this class loses the ability to kill multiple players at once and its ability to bypass death immunity is more situational while still allowing the class to kill those players in order to win.
The class should be relatively easy to tweak balance-wise. Giving Disguise Self a cooldown or a limited number of uses can power down the class if it’s too strong, or it can be given immunity to most occupy attempts and target changes if it’s too weak.
