Event Cards are usually cards which have a fire and forget effect. They are usually used during the Main Phase, and can have varying effects such as changing power, searching your deck or removing cards from the stage. Unlike Character Cards, they do not have Characteristics, Power or Soul.
Players are allowed to play as many Event Cards from their Hand as they wish, as long as they can pay the cost(s) and they have the right colours in their Level/Stock Area. Because there is no designated Area to place Event Cards when they are played, the player should place the Event Card in an open area on the mat, for example beside the deck or above the stock area. after the effect of the card is resolved, it is put in the Waiting Room, unless otherwise stated.