tortoises are knights, but sea turtles are more like traveling merchants or itinerant preachers
armadillos are also knights, but they lack lieges, and thus purpose. pangolins are astrologers, oracles, etc who wear robes of bronze scales for the aesthetic effect of the clanking and gleaming and so forth
pillbugs and other isopods are like if a siege engine or an armored supply wagon was a little guy.