The Difficulty of an attack roll against an adversary is equal to the adversary's Difficulty score. The Difficulty of any other action rolls against an adversary is equal to the adversary's Difficulty score, plus (if applicable) the value of one of the adversary relevant Experience modifiers.
When a player makes an action roll without a specified Difficulty, the GM sets the Difficulty according to the totality of the circumstances. Refer to the following benchmark table for more guidance: