HP: I started with the The Dark Dimension

A frigid wind howled through the trees as Magnus Gaunt pressed forward through the thick snow. The bitter chill did nothing to deter him; his body had long since adjusted to the cold of Narnia. His mind, however, was occupied with thoughts of his ever-growing power, the looming conquest, and the whispers of fate that seemed to follow his every move. The Sorcerer's Hat sat atop his head, its ancient magic subtly humming in his ears, while the Dragon Belt of Sun-Lok rested firmly around his waist, a newfound source of power that pulsed against his skin.

As he trudged deeper into the frostbitten forest, he could sense the White Witch's influence thick in the air, curling around the trees like an unseen predator. The time for war was approaching, but first, he had preparations to make.

Magnus exhaled slowly, watching the mist escape his lips before placing his hand on the trunk of a fallen tree. He felt the energy of his belt stir. Channeling the magic into his palm, he focused. The tree convulsed, wood groaning as it twisted and reformed, branches sharpening into talon-like wings, its hollowed-out centre morphing into a serpentine skull. The dragon's eyes flared with an eerie glow, and as Magnus stepped back, it roared to life, shaking the snow from its form.

A smirk tugged at his lips. "Perfect."

Wasting no time, he climbed onto its back, gripping the rough wooden scales as the beast took to the sky. The rush of wind against his face was exhilarating. With his new power, no terrain was impassable.

As he soared towards the White Witch's castle, a thought struck him. "System, how much time has passed in the Dark Dimension?"

[Processing…]

[Approximate time elapsed: 200 years.]

Magnus narrowed his eyes. That was far more than he had anticipated. He clenched his fist. "Open a portal to the Dark Dimension."

A swirling void ripped open before him. He dived into it, his dragon disintegrating into energy as he crossed the threshold. When he emerged, he found himself standing atop his castle's grand balcony, looming over the city he had left behind centuries ago.

The sight stole his breath.

Beneath him sprawled an empire, stretching as far as the eye could see. Towering spires of obsidian jutted into the sky, streets paved with glistening black stone bustled with shadow-forged warriors, creatures of nightmare and smoke. The city pulsed with dark magic, a realm of its own, bound by his will.

A figure knelt before him at the centre of the courtyard, clad in ornate black armour, his oni mask concealing all but his gleaming crimson eyes.

"My lord," Byakuya Kira intoned, his deep voice echoing through the air. "You have returned."

Magnus stepped forward. "I see you've been busy."

Byakuya kept his head bowed. "As you commanded, I have united the shadow creatures under your banner. Your empire is ready, and your army awaits."

Magnus glanced beyond the castle walls, where endless ranks of spectral soldiers stood at attention, their weapons gleaming in the dim glow of shadow lanterns. They were waiting for his word, ready to march at a moment's notice.

"Good." He turned to Byakuya. "Prepare them for war."

Byakuya rose to his feet. "It shall be done."

Magnus stared over his empire one last time. He would return, but for now, there was a kingdom in Narnia that needed to fall.

"System, synchronise the Dark Dimension's time with Narnia."

[Time synchronisation complete.]

Satisfied, Magnus opened another portal, stepping back into Narnia's cold embrace.

The moment he emerged, the system chimed again.

[Alert: The Stranger Things plotline has begun on Earth.]

Magnus was not surprised. He had known for some time that his presence would create ripples, merging worlds, distorting realities. The question was not if something would happen, but when.

"What's the status?" he asked.

[Anomalies detected. The Upside Down is bleeding into the mortal world. Creatures are manifesting, and Eleven has begun to develop her powers.]

Magnus smirked. Things were falling into place. While the war in Narnia was his priority, the events on Earth could not be ignored. There were valuable assets to be gained, alliances to be made, power to be seized. But first, the White Witch had to fall.

He adjusted his Sorcerer's Hat and tightened the Dragon Belt. His journey to the White Witch's castle continued, but now with the knowledge that his future battles would stretch beyond Narnia, beyond Earth, into a multiverse of chaos and opportunity.

And he would be ready for it all.