Ruling Hydreigon Dark Aura & Dark Trance

[DeepSleepDarkrai]

Ok so my question is can I move a DCE that's on the Dark Aura Hydreigon to another Pokemon using Dark Trance?

 

[King Arceus]

Yes since the energy is providing {D} at the time.~KA

 

[DNA]

...just keep in mind that when it's not attached to a Dark Aura Hydreigon, you can't move it anymore, since it goes back to providing {C}{C} instead of {D}{D}.