Aeshma let her gaze linger on the piles of dusty parchments and the vats of amniotic fluid that cluttered the corners of the room. Aeshma, whose black silk dress hugged every curve of her sculptural silhouette, paused in front of a blood-stained experimentation table. She ran a delicate hand over a metallic surface, her eyes shining with a hint of disdain.

"This is really... rudimentary for a man of your genius," commented Aeshma in a suave voice tinged with a touch of sarcasm. "I was expecting a more... orderly sanctuary for the only immortal in this world."

Konstantin, who was already handling a vial filled with a fluorescent liquid, stopped abruptly. He shot her a simple glance over his shoulder, a blank look devoid of any human emotion, before diving back into his task without saying a word. The silence that followed was disturbed only by the crackling of a magical Bunsen burner and the low hum of the surrounding machines.

The sorcerer then turned toward Lucifer, who remained motionless in the center of the room. Konstantin set down the vial and crossed his hands.

"Why?" asked Konstantin abruptly, his voice a dry growl that echoed against the metallic walls. "Why would two entities of your rank want to open the doors of the Abyss? You know better than anyone that what sleeps down there is not meant to be awakened."

Lucifer did not answer. He simply stared at Konstantin with his pupils, an intense gaze.

Konstantin held his gaze for a few seconds, searching for a flaw, a hesitation, but found only silence. Finally, he let out a weary sigh and looked away, abandoning any attempt to understand their deep motivations.

"Whatever..." murmured Konstantin with a shrug. "In the end, it doesn’t interest me. As long as I find new test subjects through this collaboration, everything is fine with me. Political or metaphysical motivations are trivialities for those who have seen centuries pass."

He took a step toward Lucifer, his face drawing dangerously close to his, a demented gleam shining in his eyes. "But be careful... do not bother me with your territory wars once the portal is open. My science requires tranquility."

Aeshma stepped forward, positioning herself beside Lucifer, her presence exuding confidence. "We have nothing against you," she accepted with a half-smile. "We respect your neutrality, as long as it serves our interests."

The sorcerer nodded, but his expression suddenly darkened. He rubbed his chin, as if an unpleasant thought had just crossed his deranged mind.

"However... your idea poses a small problem for me," said Konstantin as he sat down on a stone stool.

"What is it?" asked Lucifer in a curt tone, his hands remaining thrust in his pockets.

"The Angels," replied Konstantin with a grimace of disgust. "I don’t want the residents of the celestial city to become agitated by creating a key for the doors of the Abyss. They are already paranoid enough as it is. If they discover that I helped the demons force the passage, they will go so far as to accuse me of being part of your ranks."

He stood up and began pacing while thinking. "And as a neutral person, I refuse such accusations. I serve neither heaven nor hell, I serve only knowledge. That is why, to maintain balance and my own peace, I intend to create a key for the angels as well. If each side has its means of access, they will neutralize each other and leave me out of their quarrels."

Lucifer and Aeshma exchanged a quick glance. The proposal was bold, but strategically logical in the mind of a man who sought only to preserve his laboratory from divine retaliation. Realizing that this was the price to pay to obtain Konstantin’s genius, they nodded simultaneously, which ended their conversation.

Quickly, Konstantin set to work. The following days were a symphony of forging noises, alchemical incantations and complex mathematical calculations that surpassed mortal understanding. The sorcerer did not sleep, his immortality allowing him to work tirelessly under the stroboscopic lights of his laboratory. Lucifer and Aeshma sometimes observed him, seeing the old man manipulate aura and mana with a frightening fluidity, engraving forbidden mudras on unknown metals.

A few days later, the work was completed.

Konstantin presented himself before them, his features more drawn than ever, but a smile of demented satisfaction stretching his lips. He held in his gloved hands two objects that seemed to vibrate with energy. The first was the Key of the Abyss, the Key of Solomon, an obsidian dagger whose blade seemed to absorb light. The second was the Key made for the celestial world.

"Here is what you were looking for," declared Konstantin as he handed them the artifacts with unaccustomed solemnity. "The Key of Solomon is in your hands. Use it as you see fit."

Without wasting a moment, Lucifer seized the key. The two left Konstantin’s dwelling, immediately heading for the Gates of the Abyss, located in an area of Tenebris.

When they arrived in front of the cyclopean doors, made of a metal that did not belong to this world, the tension reached its peak. The wind howled around them, carrying clouds of ashes and slag. Lucifer stepped forward, the Key of Solomon glowing with a scarlet light between his fingers. Aeshma stood behind him, her hands concentrating her demonic energy to stabilize the area.

The two acted in perfect synchronization. Lucifer plunged the key into the immaterial lock at the center of the doors.

A deafening crack, similar to that of a continent tearing apart, broke the eternal silence of the plain. The Gate of the Abyss opened slowly, revealing a gulf of absolute darkness. Immediately, a powerful demonic energy, of a stifling density, poured out onto the outside world, mowing down the few black plants that still survived in the surroundings.

The change was immediate and apocalyptic. The sky of Tenebris, already dark, changed radically in color to blood red, as if the atmosphere itself was igniting under the influence of the corrupted mana. Flashes of blackness streaked the heavens, and a howl from the depths of the ages rose, announcing to the entire world that the seal had just been broken.

Lucifer, standing before the gaping portal, let his aura of fear extend, merging with the energy escaping from the gulf. His eyes shone with a new gleam.