The dark stallion is one of my favorites, I know him well. But, out of no-where today arrives a totally new player among the mustang stallions, he is totally white except for a darker muzzle and very similar to the other two white stallions, but younger and seemingly more fit and athletic.
He might be a stallion that I saw briefly for a day almost two years ago and then disappeared. My best guess is that he and his band of red mares lives in the next valley to the south and happened to meet my 'regular' herds as they wandered to the southern limit of their range today. I hope he sticks around.