This is Link as an adult. In the ocarina of time you have the ability to travel back and for through time and to play as Link as an little kid or as an adult.
As an adult Link has certain advantages to being a kid. He can get into palce where you have to be more "adult" to get in to that you can't when you are little. He also gets more respect for towns people.
This is Link as a little kid. In certain parts of the game you need to travel back in time to be a little kid to do stuff.
He has his advatages such as he can get though small places and can hide easier.
Saria is Link's best friend as a child, and lives in the Kokiri forest.
Just after Link pulls the Master Sword, Saria gets stuck in the Forest temple and must be rescued.
After rescuing her, Link finds out that Saria is actually one of the seven sages.
This mysterious character appears just before adult Link enters a new dungeon and teaches him a song that will warp him to the dungeon's entrance rather than have to walk all the way back to it.
The true identity of Shiek is one of the biggest mysteries in the game.
Malon is Talon's daughter and lives on Lon Lon Ranch as well.
As a child, she introduces Link to Epona and teaches him Epona's Song.
As an adult, Malon challenges Link to a horseback obstacle course, and gives him a nice reward if he can finish the course in under 50 seconds
Owner of the Zora's Sapphire, she loves Link and wants to marry him. Link does not want to because at the time he was to young.
Ruto seems to have an attitude at first, but quickly grows to like Link.
She is the Water Sage.
Impa is the caretaker of Princess Zelda and resides at Hyrule Castle.
She also founded Kakariko village. Princess Zelda helps Link get started on his journey by telling him of a dream she had in which Ganondorf was trying to take over the world.
She is the most important friendly character in the game aside from Link.