Dragon Cubes

The Dragon Cubes (Japanese: ドラゴンキューブ, Doragon Kixyuubu) are known to be the fragments of the Tenkai Dragon. After being defeated, it was split into five cubes that were scattered across planet Quarton. When the five cubes are placed on the Dragon's Nest, they are combined into one giant cube that can only be opened with either of the two Dragon Keys.

In the Series
In "A New Knight", the Tenkai Dragon was split into the five dragon cubes by the two Dragon Keys and went into each knight, granting them Phoenix Mode to defeat Vilius and fix the portal to save Earth and Quarton from colliding.

In "Vilius Returns", Dromus attacks the Tenkai Dragon, causing it to split into black and white Dragon Cubes. The white cubes contain energy from the good side of the dragon and the black cubes contain energy from the evil side of the dragon. The Tenkai Knights and Dromus absorbed the white cubes while Vilius absorbed the black cubes, which gave them new looks and powers, such as Elemental Mode for the Knights.

Colors
The five Dragon Cubes came as the same colors of the Tenkai Knights.
 * Green = Valorn
 * Blue = Tributon
 * Yellow = Lydendor
 * Purple = Dromus
 * Red = Bravenwolf

Trivia

 * If the Dragon Cubes are colored, the Knights can access Phoenix Mode.
 * If the Dragon Cubes are white, the Knights can access Elemental Mode.