When words get locked inside and demons are locked deep down the underworld with no way out of their misery, they bang the doors and smash the walls inside but all go in vain. 
Behind every smashed wall there is a wall till eternity. They cry in pain, sob in agony but the walls and doors won't let it all out for sure. They go unheard and unanswered. And then finally they give up and wait, they hear the world outside singing, dancing and playing. Happiness coming and smashing with those lofty wall and go away.
And when the fire of the underworld boil that dungeon they all choke and bite the dust, they die and rot, spreading the plague across the underworld and beyond. Sucking away all the life and turning everything stone cold with no soul. 
They're finally free...