So looking at the Rider's performance in the update I wonder what kind of foes it could take down and the average effect it would have. As we can clearly see that the single rider is enough to slaughter a decent number of goblin wolf riders without much difficulty so at the very least they will murder chaff and light cavalry pretty well.
I do love how if this works it will drastically change the calculus when it comes to dealing with Grey Wizards on the battlefield, since at the very least you'd likely need to dedicate something more valuable to dealing with them rather than getting lucky with some lighter skirmish cavalry.
If I recall correctly, it's immune to non-magical weapons, so it should be able to plough through most things—and would be potentially demoralising as well, having an invincible knight counter charge your formation. It might struggle with undead, especially since they don't have moral, so sufficiently large numbers of skeletons or zombies could just bog it down indefinitely, even if their attacks can't actually hurt it—and the more ethereal kinds of undead explicitly have magical attacks.
(of course, there's not much a sufficiently large number of skeletons can't do, so it kinda feels like cheating to use that as an example)
I also can't imagine it would fare well against most flying enemies, unless it can charge upwards—and I suspect we're using the wrong wind for that.
Hero units with magic weapons could probably face it on an even level—but that's why we have our own sword style, and a pocket knight should be enough of a surprise to interrupt an attack and give the wizard a chance to teleport away.
It should be pretty solid against spellcasters though, seeing as it's whole thing is facetanking battlemagic at close range.
I'd also normally say that a lone knight might struggle against monsters, but the apparition is just a knight shaped monster itself and can bodyslam things with its entire mass.
So flyers, martial heroes w/magic items, anything with an inherent magical attack, and hordes that won't run away after taking casualties would be the main counters as I see it. A short list, and one we're well equipped to deal with—assuming they actually have the skill to survive being attacked by the Rider. Meanwhile, anyone not on that list is going to get wrecked pretty hard.
Oh, and dragons too I guess, but dragons can murderise nearly anything, so it doesn't count.
