The different elements determine the damage in battle.
What if my card has the same element as my enemy's card?
If both cards stop in the same line, the damage is considered 0 regardless if it is a fighter card or a henchman card.
What if fighter card and henchman card of the same element stop in the same line?
The damage is increased enormously! Your goal should always be to stop fighter and henchman of the same element in the same line.
Note: If the enemy has the same element in the same line, the damage is 0.