Kairi

Kairi is the best friend of Sora and Riku. She is a Princess of Heart. She is from Radiant Garden (Hollow Bastion) and currently resides on Destiny Islands. Her grandmother's status is unknown.

Kingdom Hearts
She and her friends are making a raft when she gets whisked away to Hollow Bastion. Riku has her body at Hook's Ship. When Sora sacrifices his heart she is revived. She appears at the end and Sora promises to come back to her.

Kingdom Hearts Chain of Memories
She is replaced by Naminé with her magic and remembered at the end of Sora's story. In Riku's story she is Namines form and not forgotten by Riku.

Kingdom Hearts 358/2 Days
Kairi is only seen in flashbacks and mentioned by Riku and Xion.

Kingdom Hearts II
She comes into contact with Roxas in minds which helped Sora. She is kidnapped by Axel and Saix at different times and reunites with her friends and Nobody Namine. She gets the Destiny's Embrace and returns with her friends to the island.