We must say, it's bloody considerate of the Four Horsemen to wait until the very day we're reviewing the Undead Builder Pack to reveal their big Mythic Legions dragon and the various add-ons you can buy for it, including an "Ashen Zombie" (with the dragon's wings) that just so happens to reuse both semi-skeletal heads from the Builder Pack:
Since they're ashen grey, it's easier to identify how they're different to one another than it is on clear plastic. Good on ya, Horsies!