Surbag needs long pointies to stop their nasty charges, or they will flatten his children under their hoofs…
Ah, you spotted the weakness! I prefer narrative-driven armies, so in this case went for cheap troops in large numbers backed up by specialists. Light cavalry can be challenged by spiders reducing their mobility and bowmun whittling them down. Heavy cavalry may succeed with their initial charge but, once their lances have been taken out of the equation, Orc numbers should tell. Probably. Possibly. Um…