At the end of the Tutorial enter the referal code MQJ985055 or pre-registration code awq570792 to get a free Jean Grey card and 2,000 Silver coins to upgrade cards. The Jean Grey card is very powerful and able to dodge Attacks and pass through Defense of all of your enemies by using the ability 'Mental Break'.
Free legendary Dr. Doom and 1 million silver
To receive 1 million silver and a free legendary Dr. Doom card enter tcj035168 as a referal code. Works only once.