I always wanted to implement this role in one of my games but never had the opportunity
Time Killer
Role Description:
The Time Killer may each night choose to travel back to a previous night in the game and perform the current night's mafia faction kill on this night instead. This will mean that the mafia kill will be affected by the external influences (roleblocks, protects) that interacted with the Time Killer and their target on this previous night in the game rather than the influences of the current night. The Time Killer cannot travel back to the same night twice.
Notes:
I.e. if the Time Killer on Night 3 is chosen to carry out the mafia faction kill, they can choose to travel back to Night 1, which means that only abilities that were used on Night 1 are potentially able to prevent the kill from going through. This means if the Time Killer is roleblocked on Night 3, this will have no effect - but if the Time Killer was roleblocked on Night 1, then the kill won't go through. Similarly, a Doctor won't be able to protect the Time Killer's target on Night 3; They would need to have protected them on Night 1.