Hi.

Question about Galloping boulders card.

Galloping Boulders
Type: Treachery
Encounter Set: Over the Misty Mountains Grim
When Revealed: The first player chooses a questing character. That character takes 3 damage and is removed from the quest.
Shadow: Put this card on top of the encounter deck.

The first player must choose a questing character only from his characters or from any player's characters?

UPD: I found answer - from any player's.

Yep. It luckily doesn't say from characters "you control" so you can pick any players characters.