Valkyrie Ghost

The main antagonist during the second season. In a contrast to the rest of the cast in the series, she's a dark and uncomical character. She is not a single individual person, but rather the combined energies and emotions of the four missing Princesses of Valhalla from ancient times that saved Valhalla from the destructive Blizzard of Time. She resembles Valkyrie in her adult form, but wears black clothes, and has purple eyes, which in her fighting form turn red. She chose the name Valkyrie Ghost since she resembles Valkryies. Valkyrie Ghost is searching for the legendary Illustrious Lover (Phantom Lover in the dub) of myth in hopes that she could cure her eternal sadness and loneliness. She finds him in Kazuto after feeling the absolute joy and happiness in Valkyrie. Though she at heart simply wants to released from her pain has no malevolent intentions, she's very ruthless and has no problems hurting or killing anyone that gets in her way, once nearly killing Hydra. The missing four princesses are also the creators of Valkyrie's Key of Time, and she poses the ability to control it even when it isn't in her hand. Similar to Valkyrie, she transforms into a fighting form by kissing Kazuto. She can fly, but mostly fights by firing blasts of energy and can create force-fields. Her strongest attack consists of her bringing the eyes on her costume together and firing a combined stream of energy. She spends some time initially trying to win Kazuto's heart, and then kidnaps him when she feels she succeeded (though he didn't resist). She apparently can't be killed by fighting, since even when she was defeated by Akidra she still couldn't die. She was only stopped when Valkyrie used the Key of Time to release the emotions and energy that made up her form.

wikipedia