Gold

Like in most situations when playing a card collecting game (CCG/TCG), one is required some energy or mana to summon a card into the battlefield. Basically, that mana is the Gold in this game. The game always starts with 3 gold, and each turn, the amount of gold you start with increases by one (until you reach 10, which then only fully replenishes every turn).

Gold in the game has a number of uses apart from being the main mana pool to summon your units into battle. It is also used to put your units into guard position, to use your hero's special ability, or in some cases to activate some unit card's special ability. It is best to exhaust all your gold resources in every turn as whatever is left do not compound (add-up) on the concluding turn. Every gold left in your treasure chest in a turn gets forfeited and will fully replenish on the following turn.

Your current gold value is represented on the treasure chest sitting on the left side of your hero's icon. basically, any pertaining move to make in the game casts you gold aside from a several exceptions. First is when Ending the turn. Pressing the End Turn icon doesn't cost you gold. Also, the player going second (the game automatically picks who goes first) gets an additional card from his Deck in his first turn. This is called the trophy card. It does not cost you gold as well. There are a couple of cards in the game too that does not cost you summon or alternatively provides you additional gold when summoned.

There are a couple of tricks to the game to save up on gold (in a sense), where in you do not have to be tied in summoning feeble nits every now and then to protect you and using gold on more effective ways like using your special abilities to afflict direct damage to your opponent, or having special cards that reward you with additional gold. Keep in mind that in the game, depending on how much gold you have in the right time can mean either winning or losing the game.