An alliance that includes Skaven, Dark Elves or Hobgoblins is automatically a fragile alliance.

All relations in a fragile alliance start out normally, according to the various alignments. However, each player in a fragile alliance must roll a D6 at the start of their turn – on a roll of 1-3, all of that player's alliances immediately become one step worse for the rest of the game (unless they're already desperate allies).