@DurinVoronwe . That strikes me as a little too high in terms of threat generation. Combined with Gandalf, that's 29 starting threat with a guaranteed 3 threat increase at the end of each round. That means (barring card effects that increase or decrease threat) that you will only have 7 rounds to complete most scenarios. Add to the picture that you will only have two heroes, this strikes me as a very hard duo to justify. That could just be me though.
I love the encounter deck mechanic though. I could see increasing his cost by 2 or 3 threat, dropping the automatic threat increase, and adding to his line that at the end of the quest phase if the top card of the encounter deck has a shadow effect, he does not exhaust to defend. I don't know if this would be overpowered or not though.