 Many elements first introduced in this game have remained in the series . For instance , non @-@ player characters ( NPCs ) were present in The Legend of Zelda , but their role was rather limited . Starting with The Adventure of Link , Zelda games have prominently featured a variety of NPCs who play pivotal roles in Link 's quests . Zelda II was also one of the first games where NPCs walked around and seemingly had their own agendas , giving the world a life of its own rather than being a simple stage for the story to unfold . The use of metered magic and spells has also carried over into other Zelda games . The Triforce of Courage makes its first appearance in The Adventure of Link and plays an important role in later Zelda games , as it is strongly associated with Link . Dark Link is a version of Link 's Shadow which appears in Ocarina of Time , a similar Link clone called Shadow Link appears in Four Swords Adventures , and yet another appears in Spirit Tracks , as well as in A Link Between Worlds . 
