What happens to Rainbow Energy when it's attached to Hydreigon? Does "Dark Aura" Ability change it to ONLY produce Darkness Energy rather than all energy types simultaneously?

Since Dark Aura replaces the attached energy's original types with Darkness type, Rainbow Energy would lose its effect to produce all types of energy while Dark Aura is in effect. However, Rainbow Energy is still considered a "Special Energy Card" in this situation.

Relevant cards