Machakan Spiders?

[Halancar]

Black Hunter don't trample, so no worry there. On the other hand, they do have 20 prot, so getting through that is definitely going to require high damage weapons. Greatswordmen is probably your best bet. Crossbowmen in numbers should work too, but you will need numbers. Of knights, if you can get a good charge on them (but spiders charge back).

Part of your problem, I believe, is that once a Black Hunter dies, the spider keeps fighting (if you look closely, the rider disappears, and of course the stats change). And while the Black Hunter had only 13 hp, the spider has more, enough so that the Nature bless will really help. So, more greaswordmen, I guess (the protection does go down).

Black Hunters are 125 gold, 36 resources, sacred, and capital only, so you shouldn't see too many at a time.