At Kouh.

Everything is peaceful and quiet throughout Kouh when out of nowhere multiple Shadows, Neo Shadows, Angel Stars, Invisible, Demon Towers, and  Gargoyles attack.

Watching all this is Ciarda or Potema who is smiling at the chaos and hearts that the Heartless are gathering from the civilians.

However she frown when she see Rias and Sona alongside their peerages arrive to defend Kouh.
But what makes her frown is how Sona and her peerage are actually beating the heartless while Rias and her peerage can't.

Potema: "Tsk this will be a problem if Sona and her peerage are actually beating the Heartless which will make Rias and her peerage try to train better. Well I can't let that happen" she said then dark wings appear on her back.

She then fly into the sky and into the battle while musical Heartless appear and begin to play a classic song: Angel of Darkness.

Potema: "Angel of Darkness. Angel of Darkness. The world is in your hand. But I will fight until the end" she sing gaining everyone attention.

Rias: "Attack her!" She said only to scream as Potema throw spear of darkness that strike her.

Issei: "President!" He said only to scream as another spear had strike him but at the manhood.

Potema: "Don't follow your command but I will fight and I will stand" she sing attacking Rias peerage while the Heartless are given a boost of darkness which they used to attack Sona and her peerage.

Watching all this is Raynare and her group as they are completely mind blown at how powerful the darkness is compare to the light.

Raynare: "When darkness falls, pain is all the Angel of Darkness will leave behind" she said watching as Potema block a fist from Keneko.

Potema: "And I will fight!" She sing slashing Kiba sword into dust while the rest of Rias peerage pant.

Mittelt: "The love is lost, Beauty and light have vanish from garden of delight" she said watching as Potema block another fist.

Kalawarner: "The dreams are gone, Midnight has come" she said as Potema punch Keneko out then block lightning from Akeno

All three: "The darkness is our new kingdom" they said as Potema unleash a powerful blast of darkness that overwhelmed Akeno lightning and knock her out.

Potema: "The world is in your hand but I will fight until the end" she sing then both herself and the angels vanish into corridors of darkness.