The Curia, an organization that defends people from fiends. Aluche is an agent of said organization. One day, she receives an order from the Pope to escort a priestess.
This priestess' name is Liliana, Aluche's childhood friend.

Upon informing the Pope of their arrival at the Curia, Aluche discovers that Liliana has been chosen to be the "Bride of Time," the maiden destined to be sacrificed to the Moon Queen.
She's given the mission to deliver Liliana to the vile being, but is shocked and horrified.

"Why did it have to be Liliana? If I bring her to the Moon Queen, she's going to die...!"
Unsure of what to do, she tried to keep her personal feelings at bay in order to carry out her mission.

Aluche understood that orders are orders, but she still wanted to save Liliana...
It's then that a young woman appeared before them, blocking their path.
"Ruenheid?!" Their old friend and comrade, Ruenheid, stood in their way.
A member of the anti-Curia organization, the Lourdes Order, Ruenheid had come to them with the single objective of saving Liliana.

Representatives of the Curia and the Order, the two friends had become enemies, despite sharing the same feelings.
There was no room to compromise.
It was then that a tremendously strong demon appeared.
The two fought to protect Liliana, but the difference in power was clear. Aluche lost her life in battle...

Aluche woke up to blinding lights, surrounded by strange machines in a laboratory.
In front of her was a calm looking woman wearing a monocle.
This woman, Camilla, was one of the Curia's top scholars working on artificial half-demon research.
Under orders of the Curia, she brought Aluche back from the dead as a half-demon, using the Legendary Demon Arnice's blood...

With her memory slowly coming back to her, Aluche recalls being attacked by a demon.
She asks Camilla about Liliana, but discovers that "Liliana is gone, though there've been sightings in the Ruined City Eurulm."

With her new powers and Blood Sword, Aluche begins her battle against the fiends in the hope of locating Liliana.

Camilla guides Aluche to a hotel, her base of operations. It's there that Aluche once again comes face to face with Ruenheid.
Though their positions are different, they both have the same objective of locating Liliana.
Despite all that's happened, they still share a past together, and so they decide to work together.

The Lourdes Order decides to step in. The leader, Lady Loergwlith, sends the assassin Veruschka to take care of Aluche.
But that was not the only shadow creeping up on her. Muveil, who Aluche once looked up to like a big sister, appeared before her...
With her thoughts and feelings a mess, she continues to race through the night in order to save Liliana.