you can turn on and off the audio in game, it's in the small circle above the screen
it appears after the mission with Scar and Gunnar
after meeting Garuik, return to hut after midnight
I noticed his iron hand too, thought he lost his hand or something but in his werewolf form he is perfectly fine :))) maybe that iron hand just a glove
Fr I played it three times and still found something new :)) this game really paid attention to details. Kudos to Hyao
you just need to increase Northcrest lewd fame and do the chores in the evening