Ghulams were, like mamluks, elite slave soldiers, but usually for turkic emirs so less numerous since no emir could spend up so much as the wealthy Egypt (mamluks were the only army that defeated the dreaded Mongols in a pitched battle). Druzhina means “fellowship” and it was military formation in tribal and early feudal slavic states - heavy cavalry but entirely funded by ruler, not landed - for example polish king Bolesław the Brave was famous for having enormous druzhina.