Strife
Strife, sometimes called "War" or Conquest" commonly takes the form of a male rider in dark clothes riding a white horse. Strife has a very malleable appearance and seems to be willing and able to take more different forms than the other Horsemen of the savage west.
Some speculate that Strife is a reincarnation of Khorne though others believe Strife is a new entity. Strife and Khorne both enjoyed violence, but other than that they seem to have little in common.
A common saying was "Khorne cares not from where the blood flows, only that it flows without cease for all eternity." He also seemed to have a thing for collecting skulls. Strife seems to value the emotions of violence more than the physical result, often feeding off a long slow burning vendetta than a short bloody battle.
When Strife manifest his avatar into the West, his normal MO seems to be to fan the flames of resentment and distrust that already exist.