Kingdom Hearts has featured a lot of great characters over the years, but not all of them get the recognition they deserve, and Kairi is a fine example of this. Kairi is a Princess of Heart that has been in the series since the original game was released back in 2002. Over the years, she went from being a character that fans hoped would be a powerful guardian, like Sora, Riku, and Aqua, to having a disappointing role in newer releases.