Marvel Champions: Thor Hero Pack - Rules of Play says:
With the mythical hammer Mjolner, Thor has the power to defeat even the strongest of foes with legendary strength and power. Like all Hero Packs, the Thor Hero Pack includes a fully-playable deck right out of the box that includes 15 Hero cards, 17 cards from the Aggression aspect, and 8 neutral cards. This deck allows you to harness the power of Thor, who is rewarded for engaging and dispatching villainous minions from the field!