Sora:
The main character in the Kingdom Hearts series. Sora is 14 years old and lives in the Destiny Islands with his best friends, Riku and Kairi. One day, they decide to leave the Destiny Islands to find out where does Kairi come from, but the night before they set sail, the Islands were attacked by the Heartless and they got separated. After that, Sora finds himself to be in Traverse Town where he meets with Donald and Goofy, and their journey to look for Riku and Kairi begins. Sora is appointed then as "The Keyblade's Chosen One". 
Riku:
Sora's best friend. Riku is 15 years old, he is a boy full of self-confidence, and his friendship with Sora isn't free of a bit of rivalry. He is the one who comes up with the idea of leaving the Destiny Islands to find Kairi's birthplace. After they get separated, he ends up in Hollow Bastion where is found by Maleficent. Riku eventually becomes possessed by Xehanort's Heartless, with his heart sent to the realm of darkness where he meets King Mickey and aids him in helping Sora seal the door to the realm of darkness.
Kairi:
Kairi is a 14 years old girl who arrived to the Destiny Islands a night, without a trace of her memories on her past. Along with Sora and Riku, she decides to go on a journey to find out where does she come from, but their plans are interrupted by the Heartless and she gets separated from her friends. She was originally a resident of the Radiant Garden, but she was sent to the Destiny Islands by Xehanort a few years before the events of Kingdom Hearts in a experiment to see the connection between a Princess of Heart and a Keyblade bearer. She is one of the "Seven Princesses of Heart" along with Princess Aurora (Sleeping Beauty), Snow White (Snow White and the Seven Dwarfs), Belle (The Beauty and the Beast), Alice (Alice in Wonderland), Jasmine (Aladdin) and Cinderella (Cinderella). 
Donald Duck:
Donald Duck is the Wizard of the Disney Castle. Donald leaves the Disney Castle along with Goofy to look for King Mickey, who just had left a letter telling them to look for the person who beared the "Key" and aid him on his journey. He meets with Sora in Traverse Town and joins him along with Goofy. Donald Duck made his first appearance on Disney's animated film "Disney's The Wise Little Hen" (1934). 
Goofy:
Goofy is the Captain of the Royal Knights of Disney Castle. He embarks on a journey with Donald Duck to find the Keyblade Bearer and his missing sovereign, King Mickey. He meets with Sora in Traverse Town. Goofy made his first appearance on Disney's animated film "Disney's Mickey's Revue" (1932).
