Single Comment

From the description of the goals of the individual players: 'For the two
Foreigns, the goal is to capture the other country's king, while the
goal
of the Peacekeeper is to capture the two Foreign kings', I do not see
why
the peacekeeping force should include a king at all.  It is not necessary
for the resolution of the game.
Also, the author did not specify what happens when the Peacekeeper
captures its first king; let's say they captured the Red king.  Game is
not over: at this point it is still possible for the Peacekeepers to win.

But it is no longer possible for Black to win, even though they still
have
a king standing!  On the other hand, it is still possible for Red to win
-- by capturing the Black king before the Peacekeepers get to it. 
Somehow, this doesn't make sense.
Third, once a king (say, the Red king) is eliminated, can Red continue
playing?  If not, then it's no longer possible for anyone but the
Peacekeepers to win.  This practically reduces the winning condition for
the Peacekeepers to capturing one king -- but then there is no call for
making the forces uneven.  Furthermore, the author does not specify what
happens to the eliminated player's pieces -- are they removed from the
board?  Do they pass to the victor?  On the other hand, if Red can
continue playing kingless, it leads to the paradox outlined above.