There is a quest to free Hrothgar in Sudriland ( in Grizzleheim) You fight a boss to get a key to unlock Hrothgars cage. I fought the boss and got the message that I had gotten the key to Hrothgars cage and need to go free him I went to the cage and the ? mark over is head is not lit and if I talk to him he asks if I got the key which of course the quest said I received but it wont let me free him.
You're not supposed to talk to him, you're supposed to open the cage, which can be a little tricky. Just approach the cage slowly and you should get the option to open it.
You have to stand in a specific spot to get the X to open the cage. It only works in a small area so just walk around there slowly. It's kind of a pain.