Fight for the Castle

When Fight for the Castle enters the battlefield,
choose a player. At the beginning of your end
step, if you dealt damage to the chosen player
this turn, put a victory counter on Fight for the
Castle. At the beginning of the chosen player's
end step, if that player dealt damage to you this
turn, put a loss counter on Fight for the Castle.
Then, if there is 10 victory counters on Fight
for the Castle, chosen player loses the game. If
there are 10 loss counters on Fight for the Castle,
y