[A/N: From now on Kaiser will be called Klein]

One year earlier...

The wind was blowing over the edges of the forest that separated the kingdom of Yggdrasil from that of Babylon. Klein advanced with a steady pace, his hands in the pockets of his coat. His silver hair was partially swept back by the breeze, which revealed his cold blue eyes scanning the horizon. After saving Princess Luna, Diavolo who had just disappeared had left him a precise mission: track down the possessed and perfect his exorcist abilities. At that time, no one knew him yet under the name of Mystical Exorcist.

"Babylon... the kingdom of the dark elves..." he murmured to himself as he crossed the last trees of the forest separating the two kingdoms. He had just left the Yggdrasil border to enter the lands of Babylon.

The sight that greeted him when he reached the heights overlooking the valley was a shock...

Babylon, once famous for its majestic towers, was now nothing but a field of smoking ruins. The air was saturated with the smell of blood and burnt flesh. Among the emblematic structures that defined the kingdom’s power, only one still stood: the Tower of Sorcery.

"How is this possible?"

"What happened here?"

Klein descended the slope toward the first districts of the city. The slums that once stretched at the foot of the towers were completely destroyed. The wooden and stone constructions had been pulverized, leaving only black carcasses where a viscous mist of demonic mana clung. The ground was literally littered with corpses. Dark elves, recognizable by their dark skin and fine features, lay in positions of atrocious death. Many seemed to have been torn apart with bare hands. Others bore deep bite marks.

Suddenly, a cracking sound rang out about ten meters to his left. Klein slowly turned around.

"Grrh... Grrhhhh... Grrhhh..."

The voice was gravelly, devoid of any humanity. Heavy and clumsy footsteps struck the broken ground. After a few long seconds, a dark elf emerged from the shadow of a collapsed wall. His appearance was grotesque: his eyes were injected with black blood, dark veins throbbed on his face, distorting his features.

"So the possessed have brought Babylon to its knees? How come no one knows about it?"

His jaw hung abnormally, and his fingers had lengthened into claws. It was a possessed, a mortal whose soul had been completely devoured by a demon.

With one movement, the possessed threw himself at him with ferocity, mouth open and hands shaped like claws directed at his face. With a precise gesture, Klein shifted to the right. The possessed’s claw passed in front of his eyes only a few centimeters away, meeting only emptiness. Then, he drew his katana.

< Aura Coating >

The blade sliced through the air with a sharp whistle, decapitating the possessed in a single blow. The head rolled in the dust while the body collapsed, releasing a jet of blood blackened by corruption. Klein wiped his blade with a nonchalant gesture.

"His aura is similar to that of an A-rank warrior..."

He continued his exploration, crossing what was once a major commercial artery. The shop signs still hung on their rusty hinges, some displaying names half erased by the flames. The silence was oppressive, broken only by the distant crackling of fires that refused to go out. From time to time, a beam collapsed in a cloud of ashes, adding a dull sound to this funereal symphony. It was then that he heard a muffled groan under a pile of metal beams. Klein approached and lifted the debris with ease.

Underneath was a survivor. A young dark elf, whose leg was crushed and whose face was covered in dust and blood. His pointed ears, typical of his people, were partially torn. Klein took out a small vial of healing potion from his coat and handed it to him. The elf drank greedily, his hands trembling with terror. After a few seconds, his breathing became much calmer.

"Thank you... thank you..." stammered the survivor, his eyes raised toward Klein with gratitude.

"What happened here?" asked Klein, his voice devoid of any apparent emotion. "How could Babylon end up like this?"

"The possessed... they are just scavengers... They came after... after she passed..." he replied while wrapping his arms around his shoulders, letting out a hysterical laugh that quickly turned into a sob.

"She? Who are you talking about?" said Klein, frowning.

"The Woman of the Scarlet Night..." pronounced the survivor, his body shaken by shivers. "No one knows her exact origin... She is a madwoman who fused with the power of the demon that possessed her." He paused to catch his breath, panic distorting his features. "I saw her with my own eyes. She was smiling and crying while massacring the guards. She was smiling, do you understand?"

"She was smiling or crying? I’m having trouble following..."

The survivor grabbed the bottom of Klein’s coat, his fingers clutching the fabric desperately.

"She appeared out of nowhere. No one understood what was happening, she didn’t say a word. She just raised her hand... and the sky turned blood red." His voice broke. "Wherever she goes, nothing remains... only a river of blood."

Klein frowned once again, absorbing this information. A total fusion between a human and a demon was an extremely rare and dangerous theoretical phenomenon. From what he knew, such an event was supposed to be impossible, because the human soul could theoretically not withstand the weight of such corruption without dissolving. In most cases, the demon simply took over.

"Where is she now?" he asked while standing up slightly.

The survivor pointed with his trembling hand to one of the quite destroyed towers.

"I see," Klein nodded in agreement.

He straightened up, his gaze turning toward the still standing tower. If this woman was as powerful as the survivor described, she represented an uncontrollable variable for his future plans. He could not ignore a threat capable of razing a city as fortified as Babylon.

’ I must head to the Tower of Sorcery to meet the witch of curses, maybe I will need her help to defeat her. ’

"Leave while you still can," Klein told him without turning around. "Next time, I may not have a potion to give you."

He left the survivor and headed toward the center of the city, where the Tower of Sorcery dominated the ruins. As he approached, he noticed that the elf had not lied. Blood flowed from the city gutters, forming a viscous stream that snaked between the broken cobblestones. In places, the liquid had accumulated in warm puddles where he sometimes walked. The demonic corruption here was so dense that it became visible in the form of scarlet mist. This mist stuck to the skin and clothes like an unhealthy sweat.

As he approached, he spotted hordes of possessed coming in his direction, staggering.

"Gonna have to clean up before going there," he said to himself as he looked at the tower.