Here is a detailed description about how a fight is handled since a combat turn may consist of many fights.
Only Creatures in the ATK row may attack the opponent or his creatures.
Attacking creatures must attack a creature in the opponents ATK row if there is any. If there is no target, a creature in the RES row must be attacked. Only if there is no creature on the opponents board the opponent himself can be attacked.
When a fight occurs between two creatures, their strength value is compared. The creature with the higher strength wins and stays on the board. The other creature is put into its owner’s rest zone. The row where a creature is placed defines its strength. If the creature is in the ATK row its ATK strength is used (the upper strength value on the card). If it is in the RES row the respective RES strength is used (lower strength value on the card).
If the creature can attack the opponent directly because there are no creatures on the oppoonents board, the creature wins and stays on the board.
After a creature has won a fight its controller gains as many VP as defined on the creature card. If the defeated creature was in the RES row the player only receives half his creature’s VP value instead.
When a player declares an attack, he defines the attacking creature and the position of the target creature. If the target creature’s position changes shortly before the fight takes place or its position becomes illegal, the fight is cancelled and the attacking creature cannot attack this turn anymore.
Example 1: The defending creature is in the ATK-Row and has the ability “Fluidize” (which means: when an opponent creature attacks, it switches to the back row automatically). As soon as it becomes the target of a fight, it switches back to the RES-row and the attacked position becomes empty. Because there is no target at the given position, no fight takes place.
Example 2: The defending player has a support card in the Attack-Block Slot, which allows him to deploy a creature at any time. There is no creature in the ATK-Row of that player, so the attacker attacks a creature from the RES-Row. As soon as the fight has been declared, the defender activates his support and deploys a creature to the ATK-Row. The target in the RES-Row has become illegal, because the creatures in the ATK-Row are protecting the RES-Row. Therefore the fight is aborted.