Hidden Elm is a special device used by the ancestors of the people of Mu to control their genes to survive on their new planet as waiting for adaptations came to long. It takes the place of the Koshurishimono as the object desired by the Dragonia Kingdom.
The Hidden Elm was created as a fail safe for the spacefarers who could not survive well in their new environment and being in space for too long made their bodies grow weak. The Hidden Elm gave the aliens forms more similar to the inhabitants of Earth as well as psychic abilities in some individuals like Aila Mu. Dorado sought to conquer Mu and take the Hidden Elm so that the royal bloodline could survive as their cells were degrading due to using their psychic powers.