When it comes to the Battle for Middle-earth games, I am the maker of the Easterling faction for each one. That said, I have made extensive amounts of undeniable progress towards this end goal.
These armored horseback archers are half the middle-game cavalry of Rhûn, the other half being the less armored Variag horseback archers from Khand. In my mod for vanilla Rise of the Witch-King, the models look just like this and are for the Easterling faction that replaces the Angmar faction.
Meanwhile, in my Sub-mod for Age of the Ring, when the gamer starts a Skirmish game as Dol Guldur and chooses to be Rhûn & Khand for that skirmish, the model will be similar to this but using very different parts to kitbash it all together.
In-game, these guys get to use explosive arrows inspired by Medieval East Asian history, the same source for many of Tolkien's world-building notes about Rhûn and the Easterlings. When those hit enemy units, they do medium knock-down damage.