After Ansem is defeated, she returns to the islands, as all the worlds are "fixed". She spends the whole time between this and the start of KH II there, and she forgets Sora, just like everyone else, due to him being asleep. She has a mental contact with Roxas, and, through him, with Sora, and writes Sora a letter, which she throws in the sea. She is kidnapped by Axel and ends up in Twilight Town, where she stays until she is taken by the organization, and made prisioner in the Castle that Never was. Naminé helps her escape, and reunites with her, since she is Kairi's nobody. Kairi then gains a keyblade (out of nowhere), and fights alongside Riku, after she learns who he is.
She returns to the Island, with Donald, Goofy and the King, while Sora and Riku are trapped in the realm of darkness. Sora finds the letter that she wrote to him, and it causes the door to light to open, allowing them to return. In the ending, as she and Sora look at each other, they see Roxas and Naminé. Sora finally returns to her the Lucky Charm she lent him in KH I.
Kairi meets with Aqua, in Birth by Sleep, in Radiant Gardens, where she used to live. She unintentionally touches Aqua's keyblade, becoming able to wield one, and Aqua has the feeling that their meeting was not just a coincidence.
Xion, who looks a lot like Kairi, is made out of the memories of her that Naminé stole from Sora.
Her name means "Sea" in japanese, relating her to Aqua, whose name means "Water"
|Kairi and Naminé|
|Kairi in KH I|
|Kairi with her keyblade, in the Castle That Never Was.|
|young Kairi, in BBS|
|Kairi in KH I|
|Kairi in KH II|