House Bolton has the most-armored unit on the field of battle. The Flayed Men cavalry are clad in heavy plate armor and their horses are equally armored in thick barding. Only the toughest and largest horses can withstand the great weight put upon them by all that steel. While they might not be the fastest cavalry unit, they are certainly the hardiest. And their own war flails make enemy defenses seem pointless as the spiked balls wrap around limbs or curve over shields.