These  are  the  slots  for  creatures.  The  lower  line  is  for  your
creatures and the upper line is for your opponent's creatures.
Each turn after the player's spellcasting, the creatures he controls
attack the enemy. If the creature attacks with an enemy creature
opposite it, that defending creature's life is reduced by the attack
strength of the attacking creature. If the creature attacks an empty
slot, the attack directly injures the opponent, taking away his life.