Facecrusher was one of the three riders used by the Vampire King Swayne to protect Benzegegoth's spirit shackle from interlopers. However, the interlopers instead killed him. Concerningly, Facecrusher appears to be at least partially demonic, which is a rare occurence in the TDDC universe, where the heavens and hells are ordinarily accessible only in dreams and in death.
As a large rider, Facecrusher required a large horse. Said horse was chosen as a leadership cohort/spoil of war by Little One.