The main cards you will need are your fighters. They all have a power and an arkhome assigned to it. The cost for including a battle card to your deck is equal to the power of your card.
The first card in your deck will be considered as your Leader so choose carefully who will be your master card because the Leader gains bonus abilities.
The Field cards, which are immediately consumed once activated and do not take place on the board, confer bonuses to one or more arkhomes. These effects end after 3 turns or when another Field card is activated. Once it is activated, the player can directly follow up by placing a battle card during the same turn.
Warning: Field cards affect ALL cards on the board, including your opponent's. Think about this while building your deck and before using them, as your own Field cards could be doing you a disservice !
Also, you cannot have the same Field card in your deck more than once, unless you have an Alternative version of the card that will be considered a different card than the standard version.
To broaden your deck, you can add up to 2 Field cards, which you have to place among the 20 slots availables, leaving you only 18 slots available for your fighters.
The Deck cost (C) of Field cards is calculated from the power-up (P) granted by the card, as follows:
C = P+(200 + 2*P).
Example:+50 Field card will cost in your Deck: 50 + (200+2*50)= 50 + (200+100) = 50 + 300 = 350.