Dressed up, Ofelia proceeds to get slimmed as she walks and crawls through the tree.
As the Book of Revelations puts it, Behold a pale horse: and his name that sat on him was Death.
The people who have dominated my poor life invariably have.
He kills two of the fairies, biting off their heads in mid-air, and he nearly gets Ofelia.
I can not but believe that he meant it to have some significance.
Mark also makes an ally of Katherine "Ginger" Corrigan, a girl whom he has met in the area, and who successfully draws Poppy out about the Pale Horse organisation.