Sakon

Sakon is a petty, determined thief that plays a minor role in and a significant one in.

Ocarina of Time
In Ocarina of Time, his character is very minor. He can be seen running around the Hyrule Castle Market looking very suspicious, so it could be assumed that he is either buying things or stealing from the stalls. If Link talks to him is only line is "I'm late... I'm late for a very important date" which is quoting the White Rabbit from Lewis Carroll's Alice in Wonderland. In the ending credits, he can be seen dancing around joining in with the party.

Majora's Mask
In Majora's Mask, Sakon is a nasty and cunning thief, a much more virulent character than his Ocarina of Time counterpart. He is a very sly and suspicious character, although he always tries to act cool. His hideout, Sakon's Hideout, is situated in Ikana Canyon with a huge boulder placed in front of it and can only by opened by Sakon himself. He can be seen in North Clock Town in the first night trying to steal a Bomb Bag from the old lady of the Bomb Shop in West Clock Town. Link can retrieve the bag by striking Sakon with his sword, which will guarantee the Blast Mask for Link from the Old Lady, or murder him by detonating the bag with an arrow or the Hookshot or another bomb, although Link won't be able to retrieve the Blast Mask this way. He steals the Sun Mask from Kafei and is later followed by him into his hideout to recover the mask and keep the promise he made to Anju. Sakon can also be seen in the lower place in Ikana Canyon running in circles. There he will try to supposedly steal Link's sword asking "can I see it?" but thanks to Tatl he ends up giving Link some useful tips. It is unknown where he is after Majora's Mask is defeated.

There is evidence that he is also part of the Curiosity Shop. He can sometimes be seen outside the Curiosity Shop at night, where talks about how the Curiosity Shop Guy is unfair, and that he "just wants his fair share." If Link allows him to rob the old Bomb Shop Lady, the Big Bomb Bag will be sold at the Curiosity shop the next day, and the shop's owner mentions that it belongs to the Bomb Shop.

Trivia

 * In Majora's Mask, Sakon is the first non-playable character that can be killed in a Zelda game.