Seer

Played on an 8x8 board, Seer is a game of secrets. At the beginning of play, one player is randomly chosen to play the role of the Seer, the only public role. The Seer then randomly distributes the five (or more if optional roles are included) other roles to  the other players.

Each player in turn places their piece somewhere on the board. Turn order is chosen randomly, but the Seer is always first. After each piece is placed, players may go through turn order again and change the location of their piece, but the relative positions of any two pieces may not be repeated without permission by the owner of the other piece. Once every player is satisfied with their starting position, play commences.

Each turn consists of a move and cannot be skipped. Some roles have the ability to kill other players, and may only kill one player per turn. Killing a player when you have the opportunity to is not mandatory.

The Roles:

Seer
Wins if no other win condition is fulfilled after fifteen rounds
Knows who every player is
Moves as a chess queen
Cannot be killed

King
Wins if the Assassin and the Black Knight are dead
Knows who White Knight and the Black Knight are, but not which is which
Moves as a chess king

White Knight
Wins if the King is alive and the White Knight kills the Black Knight
Knows who the King is
Moves as a chess knight, but may choose to stop on any space on the way rather than leaping
Can kill a player if they end their turn two orthogonal spaces away

Black Knight
Wins if the Black Knight kills the White Knight and then the King
Knows who the King is
Moves as a chess knight, but may choose to stop on any space on the way rather than leaping
Can kill a player if they end their turn two spaces away in any direction

Assassin
Wins if the Assassin kills the King
Knows who the King is
Moves as a chess bishop and a chess king
Can kill a player if they spend two consecutive turns within one space of the Assassin

Innocent
Wins if no other victory condition is met by the Innocent's fifteenth turn
Moves as a chess bishop and a chess king
While a player is within one space of the Innocent, they cannot be killed
Killing the innocent reveals your identity to everyone

Jester (Optional)
At the start of the game the Jester secretly selects another player, other than the Seer, whose role they do not know. The Jester gains all the traits of this role, and by consequence knows which role this player has.

Inquisitor (Optional)
Wins if the Inquisitor kills the Assassin
Moves as a chess rook. Can move as a bishop only if moving towards an identified Assassin.
May identify any player that ends their turn within two spaces of the Inquisitor, revealing their true role to the Inquisitor. This is done instead of a kill, so an Inquisitor cannot identify and kill a player in the same round.
Can kill an unidentified player if they end their turn within one space of the Inquisitor. Can kill an identified Assassin if they end their turn within three spaces of the Inquisitor. Cannot kill an identified King, White Knight, or Black Knight.

Pariah (Optional)
Wins if the Pariah is killed
Moves as a chess queen and a chess knight

Blood Knight (Optional)
Wins if the Blood Knight kills the White Knight and the Black Knight
Moves as a chess knight, but may choose to stop on any space on the way rather than leaping
Can kill a player if they end their turn two spaces away in any direction

Prince (Optional)
Wins if the Assassin and the Black Knight are dead
Moves up to three space orthogonally
Can kill a player if they end their turn within two orthogonal spaces
If the King is dead, the Prince gains the ability to move as a King. In addition, they become the King for the purposes of the White Knight, Black Knight, and Assassin's win conditions.

Notes:
-The King and the White Knight can share victory if bother of their win conditions are met at once (i.e. the Assassin is dead, the King is alive, and the White Knight kills the Black Knight)
-In the case of a Jester-King, both Kings share a victory. To win the game the Assassin and Black Knight must kill the true King, and the White Knight requires the true King to live. The death of the Jester-King also does not count for the purposes of advancing the Prince.
-In the case of a Jester-Assassin, Jester-White Knight, Jester-Inquisitor, or Jester-Pariah, only one between the Jester and their counterpart can be victorious. For the King to win both Assassins must be dead. For the Black Knight to win they must kill the true White Knight.
-In the case of a Jester-Black Knight or a Jester-Blood Knight, the Jester and their counterpart only share the victory if they share the kills. If either player performs both kills, they alone are victorious. For the King to win, both Black Knights must be dead. For the White Knight to win, they must kill the true Black Knight.
-In the case of a Jester-Innocent, both Innocents win if they are both alive at the end of the last turn either of them has. If one of them dies, only the surviving Innocent can win.
-In the case of a Jester-Prince, they require the death of both the King and the true Prince to be advanced as if they were a Prince with a dead King.
-If the Inquisitor investigates the Jester, they are not told which role the Jester is mimicking, only that the player is a Jester.
-If a player performs an action that their role cannot do, they are disqualified from the game.
-When playing with optional roles, it must be decided publicly before the game which roles are in the game.