north Drachvald Spur door key

There is a door half way up a hill in the scene that I cant find the key too, I've killed the bandit boss for his key and that opens the treasure room where he is, any ideas where to find the other key?

 

there's a sluice gate on a hillside somewhere.

 

the key from the bandit boss opens both doors in that section. And i ran all over that zone looking for Arctic wolf Destroyer too....never did seen one.