Kairi's Grandma

Kairi's grandmother was an elderly woman who resided in Radiant Garden and presumably has a close connection to Kairi. At the Hollow Bastion library, she relegated a young Kairi to a story about the light and the birth of the darkness coveting the light. Thanks to Kairi's heart being transplanted into Sora during the destruction of Destiny Islands, Sora was able to access Kairi's apparently lost memory of her grandmother telling her the story of light and darkness. Later, after Kairi is restored to completion, Sora, upon meeting Kairi in the Underwater Cavern in Traverse Town, acknowledges that there is a deeper meaning to this story, and stated that it was "more than just a fairytale".

Kingdom Hearts Birth by Sleep
Kairi's grandmother first appears in terms of story chronology in Kingdom Hearts: Birth by Sleep, shown to be holding hands with Kairi while Aqua is in the background watching.

Kingdom Hearts
She only appears when Sora expericed Kairi's memories. In the flashback, Kairi's Grandmother told her a story.


 * Long ago, people lived in peace, bathed in the warmth of light.


 * Everyone loved the light.


 * Then people began to fight over it.


 * They wanted the light for themselves.


 * And darkness was born in their hearts.


 * The darkness spread, swallowing the light and many people's hearts.


 * It covered everything, and the world disappeared.


 * But small fragments of the light survived... in the hearts of children.


 * With these fragments of light, children rebuilt the lost world.


 * It's the world we live in now.


 * But the true light sleeps, deep within the darkness.


 * That's why the worlds are still scattered, divided from each other.


 * But someday, a door to the innermost darkness will open.


 * And the true light will return.


 * So, listen, child.


 * Even in the deepest darkness, there will always be light to guide you.


 * Believe in the light, and the darkness will never defeat you.


 * Your heart will shine with its power and push the darkness away.


 * Do you understand, Kairi?

In the KH Manga series, the fairytale (with some modifications) is used as a prologue to the story.


 * Long ago, the world was united and filled with warm light.


 * People loved the light, and eventually began fighting over it.


 * Then, Darkness found its way into people's hearts.


 * Darkness consumed the hearts and light of the people,


 * and in a flash it spread...


 * The world disappeared into the darkness.


 * But a glimmer of light remained in the hearts of children...


 * Children gathered their glimmers of light and recreated the worlds.


 * The recreated world, however, was no longer united...


 * It was divided into several smaller worlds.


 * Because the true light was still hidden deep within the darkness...

Trivia

 * One line from the grandmother's story, "Even in the deepest darkness, there will always be light to guide you", is a recurring theme in the Kingdom Hearts series. It could very well be an allusion to Kingdom Hearts, which is situated deep in the Darkness. This line was uttered in different words by Sora, Riku, Naminé and King Mickey. Tetsuya Nomura, according to Director's Secret Report XIII, used this same line for the formation of the final scene of Kingdom Hearts II in Dark Meridian, where the shore was situated in the Realm of In Between whilst the sea was situated in the Realm of Darkness. The Door to Light opening in the water is reminiscent of this line.


 * The grandmother's name and history remains in the dark, though she is presumably deceased prior to the events of Kingdom Hearts, as she makes no further appearance in the series and is not mentioned after the first game. But, with the inclusion of her character in Birth by Sleep, her name may be released. Also, her presence in the Library of Hollow Bastion may or may not indicate some family connection to Ansem, as it may simply have been that no other suitable place for the storytelling existed at the time of the game's production. Though Kairi's status as a princess may be purely metaphorical, it may hint at her, Ansem, and this woman being related.