Twilight

Twilight represents the realm in between Light and Darkness. It borrows powers from both forces, using both elements in ways that would not be the norm. It is relatively unknown as even King Mickey was not aware of it until realizing the path Riku took. But nonetheless, the existence of this element allows many that were normally against the darkness to accept it as something that can be used for good.

DiZ refers to this path as "the twilit road to nightfall" but Riku calls it "the road to Dawn". Xemnas refers to it as "Nothingness". Since the nobodies, who are said to be twilight beings, possess neither light nor darkness it can be assumed that there are two different interpretations of the term twilight: the first being Riku's twilight which indicates a fusion of light and dark, and the second being a broader definition encompassing all that does not fall under light or dark. Worlds that are tied to both Realm of Light and the Realm of Darkness are known as twilight worlds (Twilight Town and Traverse Town are notable examples).

While it is never fully established, it can be assumed that Riku's keyblade "Way to the Dawn" represents Twilight, though its true nature and origin remain unknown