Final

In the two films (The Devil's Backbone and Pan's Labyrinth), the outward appearances of the monsters are completely different. In The Devil's Backbone the monster is not so much a monster at all. It's a young boy ghost who has a bloody gash on his head. In the film at first the ghost is treated something like a messenger, he speaks only to Carlos and isn't exposed much. Even though as I stated the ghost is just a boy he's still frightening but, Carlos in a way communicates with the ghost. The ghost gives Carlos messages of who killed him and this is the more sentimental side of the ghost. The reason I say sentimental side is because at this point of the film the ghost of course has that terrifying presents because of the glimpses the cinematographer give of the ghost, but hasn't killed anyone or caused any one's death. Before you find out the ghost is the missing boy there is a feeling he's trying to reach out. I would say that overall Del Toro treats the monster or ghost in The Devil's Backbone as a soul who's looking for closure. I didn't see Pan's Labyrinth so I don't know exactly how Del Toro treated the monsters.