Death, With Hell following close behind, Death carries with him a violent wake that rattles through the skulls of the undead, causing a spectacular cranial explosion for any zombie it comes in contact with
Famine, Attracting a swarm of insects wherever it travels, Famine's thin shadowy frame and crimson eyes mask an everlasting stamina.
Pestilence, A ghastly harbinger of plague and disease that's easily identifiable by its exposed wounds and ocular hemorrhaging, Pestilence possesses an exceptionally high pain threshold.
And my favorite,
War, Given power to take peace from the earth, the fiery red horse known as War ignites a trail of flame upon all those in its path, turning the living and the undead alike into smoldering ash.