How to play Quantum Mafia

The Derivative Game

Quantum Mafia is derived from the much simpler game "Mafia." Although the two are similar in name, the concepts and strategies differ radically between the two. As such, it is not essential to understand normal Mafia before playing quantum mafia; however, it would probably help. (Rules for Normal Mafia)

The Goal

Each player in the game keeps track as God of his or her own game of Mafia, in which they've appointed all other players to the various jobs. The winning God is the one whose game ends with a victory for either side (Townspeople or Mafia).

Procedure

Initially, each god appoints the other players to jobs in their own game. If you have N players, this will result in N different mafia games, each possessing a (possibly) different assignment of players to jobs in the game. Players are not informed of their position in any game. The various jobs in the game are explained below.
Once this is done, a normal day of Mafia beings with the players accusing each other and voting. A vote "passes" when a majority of all players votes to kill a particular person.

However, each god individually determines whether that vote was successful in their game based on the people who are alive and dead in their own game. So, just because someone gets enough votes to be "hung" in the global quantum mafia game, they don't necessarily die in your own mini mafia game. These results are not reported to any of the other gods.
All players then go to sleep, but, being omniscient gods, keep their heads up. Each player points at one other player, signifying their night action.

Each god notes who points at who and then resolves the heinously complicated nocturnal actions (aren't they all?) based on who holds what position in their own game. The processing of the nocturnal actions is complicated enough to warrant its own section (see below). As with the daytime actions, the results of the nocturnal activities are also kept secret.
Repeat until someone wins.

Nocturnal Action Order

During the night players point at each other in arbitrary order. However, the order in which their actions processed is determined by their position in each god's game (meaning that each god will likely be processing each player's pointing in different orders). The order in which nocturnal actions are processed is as follows:

The mafia assassinate
The medic(s) try save people from the mafia
The necromancer(s) attempt to add another minion to his ever-growing hoard of undead
The priest(s) attempt exorcise the undead (or really anyone they can get their hands on.

Jobs

Mafia - The usual. To assassinate someone at night, half or more of living Mafia must agree on a victim and there cannot be a tie. For example, two mafia must agree to kill anyone while only 2 of 4 mafia need agree as long as the other two make distinct votes.
Medic - If a medic points to the same person as the mafia targeted, that person is saved from assassination (for this round ...).
Necromancer - Raises the dead; commits massive vote fraud.
Priest - Exorcises undead. Undead player is returned to a normal metaphysically challenged state when pointed at.
Ghost - This "job" simply entails being dead at the outset.
Townsperson - Like everyone else, townspeople engage in their civic duty to lynch unpopular individuals without the formality of a trial but are otherwise unremarkable.

Undead

When a necromancer points at a dead player, that player is wrenched from the peaceful slumber only afforded to those lucky enough to be unceremoniously lynched by their fellow townsfolk or inventively murdered in their sleep by some enterprising Italian gentlemen. The newly raised player, in addition to being damned to wander the streets seeking tax reform, fall under the sway of the necromancer that raised them. Whenever their master casts a vote to lynch someone during the day, all his or her zombies are forced to vote similarly (regardless of their political leanings in life).

When a necromancer dies (mafia assassination or lynching) all his or her zombies return to their normal RIP state (wherein they flood various chat lists with unsolicited links to a multitude of amusing, but nevertheless distracting, pictures).

Most of the iFAQ is devoted to the sticky intricacies of undead. If you really want to know how undead work, I suggest you check it out.