Yeah... please no mellophone. I'm sorry, but that instrument just sounds so bad! I apologize for any mellophone players, but I'd rather feature an instrument with a wealth of historical and cultural background over an instrument designed to play horn parts on a football field.
It would be weird if he had a modern French Horn, but my totally awesome idea is for him to play a hunting horn. It totally goes with the "wild" theme of the game, and makes sense, since you'll be hunting this game, and you can probably loot some cheap ones from Bokoblins. And there are some...