Her name is Gekkou Chou (which translates to Moonlight/Moonbeam Butterfly). I am not sure if I should make her Galactic or Nightmare. Any idea which will fit better?

Personally I think Galactic would work better, seeing how the translation has the word 'moon' in it.

I think Galactic fits the name but go with the color you like best.

I think I'll go with Galactic, then. Thanks you 2. ^_^