A/N: Hello my wonderful followers, readers, Supernatural and Shadowhunters/mortal instruments fans! Sorry that this chapter took a bit, I wasn't sure what direction I wanted to go. And I did post it once but I deleted it for editing. I'm pretty happy with it now. And this one is a little shorter than the others, but it just felt right and I liked where it ended. Anyway I hope you guys like the villain because you always have to have a villain. Please enjoy!

Carry on wayward supernatural fans, and happy patrol shadowhunters.

Matthias Ainsworth stood before the expansive bay window, the weight of the ancient book in his hands a tangible symbol of the power he was about to unleash. As he gazed out at the glittering expanse of the city below, he grinned to himself. New York was just the beginning - his ambitions reached far beyond its borders. The world itself would kneel before him, every corner of the globe falling under his dominion. The thought of the new Clave, unaware of the impending storm he would bring upon them, only fueled his insatiable hunger for control. It was a hunger that would not be sated until the entire world lay at his feet, trembling in submission to his will.
The failures of those who had come before him only fueled his determination to carve a path to victory. The convergence of realities was merely a stepping stone in his grand design, and now, with the coveted Compendium in his possession, he could feel the intoxicating allure of ultimate control beckoning to him. It was as if the universe itself was whispering his name, promising him the dominion he had always craved.
The Shadowhunters had been oblivious to his watchful gaze from the shadows, consumed by their own battles while he meticulously laid the groundwork for his ascension to power.
Matthias sneered at the limitations that had held back Valentine and his son, recognizing their narrow vision for what it was - a feeble attempt at greatness. But now, with the reality merge unleashing unprecedented levels of magic, the world was ripe for the taking. The boundaries that had once constrained the ambitions of others were now mere illusions, and he saw a boundless realm of possibilities stretching out before him. It was a canvas on which he alone held the brush, ready to paint a masterpiece of power and influence beyond anything the world had ever seen.
The shadowhunters and hunters will be too preoccupied with their newfound adversaries, battling against the relentless onslaught of creatures and demons. They won't even sense his approach, the intricate web of his strategy eluding their grasp. Every piece of the puzzle falls into place, painting a picture more captivating than he dared to dream. This is where Valentine faltered, exposing his intentions to the enemy, but Matthias operates from the enigmatic depths of the shadows, his machinations shrouded in secrecy. The stage is set for his grand maneuver, an opus of cunning and finesse crafted in obscurity.
Waving his hand in front of the window, the surface shimmered and then reformed. There stood Magnus Bane, conversing with Sam Winchester on the balcony. Magnus was his sole concern; Matthias needed to divert the attention of the high warlock of Brooklyn. He couldn't afford for Magnus to discern his intentions. The question lingered in his mind – what distraction could Matthias employ? Perhaps something involving his prized shadowhunters?
Waving his hand once more, the image transformed to reveal Andra, the adopted daughter of the Lightwoods. His keen eyes caught the subtle glances she directed toward Magnus. A mischievous grin spread across his face. "Oh, what's this? Andromeda is harboring a secret affection for her older brother's boyfriend? How intriguing," he mused aloud, relishing the potential implications of this unexpected revelation.
He continued to observe her interactions with Magnus. "Well, well, well, what an interesting discovery," he remarked to himself, envisioning the myriad ways in which this revelation could be leveraged to his advantage.
He maintained his watchful gaze on Andra, even as she returned to the institute. Engaging in conversation with Jace and Addy for a while, she eventually withdrew to the seclusion of her room. His fascination deepened as he observed her remove her contacts, unveiling her strikingly bright pink eyes. "Well, well, well," he mused to himself, running a finger along the cover of the book. "It appears that Andromeda Lightwood's youngest daughter harbors many secrets indeed." Her enigmatic allure presented an opportunity yet to be fully realized.
She must truly feel so isolated, concealing both her emotions and her fae lineage from her family. The weight of her hidden truths must burden her with a profound sense of loneliness. And he could exploit that vulnerability to further his own agenda. However, he knew that he must proceed with caution, treading lightly to avoid arousing any suspicions. It would be prudent to observe her closely for the time being, analyzing her patterns and vulnerabilities before making his next move. After all, understanding her isolation and leveraging it to his advantage would require a delicate and meticulous approach.
Waving his hand over the window, the images vanishing as he turned and placed the worn Compendium down on the desk, its leather cover creaking slightly as it made contact with the surface. With this book in his possession, everything would be his. The weight of its importance settled in the room, casting a shadow over everything else. He knew that from this moment onward, his destiny was inextricably tied to the ancient knowledge contained within these weathered pages.
He grinned to himself as he carefully opened the book, the pages crackling softly as they yielded to his touch. The ancient tome's pages yellowed with age and bound in cracked leather. The ominous symbols inscribed on its pages seemed to pulse with an otherworldly energy. He reached for the knife. As the blade pierced his skin, a single drop of crimson fell onto the page, merging with the arcane script.
A shiver ran down his spine as the symbols began to glow with a sinister red light. The glow intensified, swirling and flowing like liquid fire, enveloping his hand and snaking its way up his arm. A surge of power coursed through him, intoxicating and overwhelming. The very essence of the underworld was now coursing through his veins, filling him with an insatiable hunger for dominion.
Yes, he has now become bound to the ancient grimoire, his soul irrevocably tethered to it. But the allure of omnipotence was too potent to resist. He embraced his newfound fate, knowing that the world would soon kneel before him as its new deity. The price of his soul was but a trifling sacrifice in exchange for the promise of absolute control and the reshaping of the future to his own design.
Mathias's voice barely rose above a whisper as he invoked a name that sent shivers down the spines of even the bravest shadowhunters. The name of a greater demon, a name steeped in dread and whispered in hushed tones only in the darkest corners of the Nephilim's world. Yet, he spoke it with a steely resolve.
He is ready to seize control, to show the Clave and all those what a downworlder was truly capable of. For the world to witness the unyielding will of a downworlder, a force to be reckoned with, and a harbinger of change.