We are starting another serious arc- the 4th straight one. So, Utsuro is starting a universal scale war just to end his literally endless misery being an immortal? What will this arc be called?
Even with the rough translations, it's still kind of hard to understand what's going on. So the key (the hand) wouldn't work if it is removed from its body, but Utsuro managed to do that by putting his blood in the hand, thus making the key his.