Players scattered across the continent are engaged in a game. Each player has certain attributes, including skill, strength, courage, cunning, and daring. Each has his kingdom. Each can ally with or attack any of the others . . . But one player seems to have confused the reality of the game with the reality of the world: a player with the attributes of machinelike precision and mechanical ruthlessness. His name is Octagon, and he's out for blood. Even though he doesn't have any.
Used availability for Fred Saberhagen's Octagon
September 1987 : USA Paperback
July 1981 : USA Mass Market Paperback
May 1985 : UK Paperback
February 1984 : UK Paperback
April 2015 : USA, Australia, Canada, UK Kindle edition