Board Thread:Questions and Answers/@comment-6082106-20130123200924/@comment-5706972-20130123204822

Cards of your element receive an element boost. The skills of your front line also play a part - some cards have an affect to 'All' which will provide the effect regardless of the element. Only the cards in your front line will activate skills, and only a maximum of 3 skills will activate in an attack/defense.