Why do you think the months in the autumn all end with EMBER? See they show you the night time with the light of the moon in the shape of a heart So you see, the darkness that is swallowing riku is the setting of the sun and the light that sora touches is the light that that moon touches when the sun sets when the moon REflects the suns re's or rays Sora, trying to help Riku, struggling in the darkness, touches that light and temporarily the Keyblade goes to Sora At the moment when Sora enters that darkness, the light you can see is the light of the heart. In the Destiny Islands when Riku is swallowed by the darkness, there's a sparkle of light, and next comes the scene where Sora first gets the Keyblade, right? In my setting, the darkness wrapping itself around those two is the darkness of Riku's heart. the time of the death of the sun where the moon touches the light of the sun and becomes the ruler or master or the light of the world.Ībout Riku being the rightful owner of the Keyblade - why is it that Sora had the Keyblade first? The next cut scene we see is actually at the darkness of night time. The next time we get a destiny islands cut scene, its also at twilight and we here that 'riku' is changing as the sun is setting. There are many world but they share the same sky, one sky, one destiny, the are talking about the destiny of the sun and its setting.

Rikus 'changing' if you pay attention, was happening at twilight. notice how one icon shows you the sun bright an shiny while the other shows you the setting sun. The place where the sun is destined to set or descend into the darkness.

Magic mirror kingdom hearts unchained