"Purchasing" Cavalry requires construction of the League of Riders and Order of Knights. Cavalry units at the early stages of the game become highly rated in attack despite the extra food costs due to attack stats and carrying capacity being far superior in comparison to infantry.
Knight Highly proficient Knights are fast and furious when it comes to raiding. Propelling a player further ahead in the game, a substantial number of Knights can be a valuable resource.
Great Lord Though slower than Knights, Great Lords can hit harder with a greater capacity to bring home the goods, effective, efficent and a force to be recond with while at the pre Occult stage of the game.
Occult units are "purchased" in the Council of Mages. However, whether due to Battlegrounds or Lost Arts, when Occult units come into play in Stormfall, they become a game changer on many levels; tactics and tenacity are des rigeur for survival and battlefield losses become somewhat harsher than decimating.
Warlock Excluding Bestiary units, Warlock "purchasing" looks initially expensive and is in fact quite slow. However, they are very effective and loss of these units will be felt considerably.
To produce these units players must first build the Hall of Shadows. Bestiary units are initially expensive and time consuming to produce, but after the initial investment of both, they can more pay for themselves.
Wyvern The Wyvern in quite a formidable foe, with some players favoring them over Dragons on the basis of their farming speed, despite their lesser carrying capacity. Naturally, in comparison, they are cheaper and quicker to produce.