Link is the main protagonist of the games
Zelda is the princess, not the main character
Ganondorf is the main antagonist
In each game, it is a different Link and Zelda with different personalities and different looks
Example:
Link and Zelda in Wind Waker
In Wind Waker, Link meets Zelda at the beginning of the game and they become better friends as the game progresses, Zelda has a much more sarcastic personalilty in this game, but knows when to be serious.
Link and Zelda in Skyward Sword
In this game, Link and Zelda are very close friends, and have been together since childhood. Although they are not really a couple, they obviously show interest for each other through out the game. Zelda is very light hearted but likes to boss Link around alot.
Twilight Princess
In Twilight Princess, Link and Zelda are not friends, they aren't a couple, in fact, they barely know each other. She talks directly to Link about once or twice in the entire game, most of her dialogue is towards Midna. This Zelda has a much more serious personalilty, unlike the two listed above.
