Niko

Niko is a member of Tetra's pirate crew who makes an appearance in The Wind Waker, Phantom Hourglass, and Spirit Tracks. He is the skivvy and the lowest-ranking crew member on board pirate ship, often having to deal with humiliating tasks like washing the dirty underpants of the rest of the pirates. Any new member aboard Tetra's pirate ship has to report to Niko for duty.

The Wind Waker
In The Wind Waker, Niko enthusiastically befriends Link when he is reluctantly cast below the decks for a journey to the Forsaken Fortress; as with Link's presence, Niko himself no longer had the worst repute on board. Niko's apparently notorious incompetence leads him to be outwitted by Link on several occasions and has him hand over multiple important treasures to the hero as rewards for completing his challenges. When Link first meets Niko, the young pirate gives him a test which all new pirate swabbies must take, which is to swing from platform to platform using ropes hanging from the ceiling and reach the other end of the ship. Niko is confident that it will take Link at least a year to successfully complete the test, but is astounded when the young hero easily finishes the trial. For his great skills, Niko bestows upon Link the Spoils Bag, and tells the young hero that he is proud to have him as his underling.

Later, when Link visits Windfall Island to find out what the pirates are up to, the young hero finds Niko stuck looking out for the pirate ship while the rest of the pirates are out having fun. He mentions that he is happy to see his "old swabbie" again, and gives him another test similar to the one he took first, except this time there are no platforms in which Link can step on to and must swing directly from rope to rope to the other side. Once Link successfully finishes the trial, Niko will once again be amazed (especially since that's a test he hadn't even passed himself) and hand him over some of the bombs that they acquired from the Bomb Shop, although somewhat reluctantly since he's afraid he might get caught.

In one of the letters that Aryll writes to Link later on in the game, she mentions how Niko seems sad that Link is not around anymore, and asks whether they used to be good friends.

Niko makes a final appearance in The Wind Waker during the game's ending. After Link and Tetra resurface from the sunken Hyrule Castle, Niko, along with the rest of the pirate crew and a few other character, greet the pair aboard their pirate ship. Gonzo is then seen steering the ship as Link, Tetra, and the gang of pirates set sail from Outset Island in search of new lands.

Like the rest of the pirates, Niko bears a striking resemble to a man portrayed in a wall painting hanging in the sunken Hyrule Castle, which heavily hints that the man could be Niko's ancestor serving under the orders of a past Princess Zelda.

Phantom Hourglass
In Phantom Hourglass, Niko recounts the events of The Wind Waker during the game's introduction before the Ghost Ship appears; however, Niko's role is severely limited in the game and only makes an appearance during the opening and closing sequences of the game. He is last seen when Tetra and Link reunite with the rest of the pirate crew. He is fond of his paper cutouts, a character traits that he keeps in Spirit Tracks.

Spirit Tracks
Niko makes an appearance in Spirit Tracks as presumably one of the few, if not the only, surviving founders of Hyrule. In this game, he appears as an ancient man (Spirit Tracks takes place 100 years after The Wind Waker and Phantom Hourglass, both of which took place in Niko's youth) who keeps pictures and memorabilia from his pirating days in his home. He narrates the opening cutscene of the game, just as he did at the opening of Phantom Hourglass. Later on, he gives Link the Stamp Book after musing about how Link looks like an old friend of his (an obvious allusion to the Hero of Winds). By putting ten stamps in the book, Niko will give Link the Shield of Antiquity, which he claims used to belong to a friend of his (given its appearance, it is evidently the same shield Link used in Phantom Hourglass; another hint that Niko's old friend was the Hero of Winds). By putting fifteen stamps in the book, Link can switch back and forth between his his Engineer's Clothes or Recruit Uniform at any time by speaking with Niko. By putting twenty stamps in the book, Link receives a scroll allowing him to use the Great Spin.

Trivia

 * Niko is one of the few characters in the series that is not a final boss, to have lived long enough to see Link of another generation.