Time passed swiftly.

More than two months had gone by since the engagement, and the year was drawing to a close.

After their betrothal, Sylas and Arwen were finally able to confirm their relationship publicly. Though they were not yet married, they could at last appear together without secrecy or restraint.

Sylas still felt a trace of regret that he could not yet call Arwen his wife, but he took comfort in the freedom to hold her hand openly, to walk beside her beneath the starlight, and to share quiet moments without fear of gossip or tradition.

For a time, the two were inseparable. Their footsteps traced every path of Rivendell, Lothlórien, and even the old ruins of Weathertop.

Fishermen on the lakes of Hogsmeade, at the foot of Weathertop, would sometimes glimpse their lord from afar, walking beside a radiant Elven maiden or laughing as he teased the white Araw Cattle grazing near the shore.

During these peaceful months, Sylas even hosted a grand birthday banquet for Bilbo at Hogwarts Castle, gifting him a bottle of the Elixir of Life as a token of friendship.

Life was tranquil, and Sylas might have remained in that peace indefinitely, until a long-awaited event drew him back to his true calling.

By year's end, the potion he had been brewing for over six months was finally complete.

The Felix Felicis, the fabled Liquid Luck, shimmered in the amber flask before him. Drops of gold rippled across its surface like molten sunlight. Sylas smiled with satisfaction.

At last, success.

He carefully poured the potion into three small crystal bottles, each filled with enough golden liquid to grant twelve hours of extraordinary luck.

Each bottle held three or four sips. One sip alone could bestow three or four hours of perfect fortune. Yet even miracles had limits. Overuse of Felix Felicis led to dizziness, reckless behavior, and dangerous overconfidence; taken in excess, it was fatally toxic.

Even the famed Potion Master Horace Slughorn had dared to drink it only three times in his life, once at twenty-four, again at fifty-seven, and a final time during the Battle of Hogwarts, when he miraculously survived unscathed.

Sylas planned to keep one bottle for himself.

The remaining two he divided further, creating four smaller vials, each granting six hours of luck.

One he gifted to Glorfindel, in gratitude for his earlier gift of Elven blood, ten precious drops, enough to brew ten cauldrons of Felix Felicis.

One he gave to Gandalf, for his guidance and companionship.The last two he offered to Arwen and Elrond, tokens of affection and respect.

Though curious, none of them dared to drink it immediately. They all understood the potion's value and danger. Instead, they kept their bottles close, to be used only in moments of dire need.

As for Sylas, he could hardly resist testing his creation. For months, he had been studying Animagus transformation, hoping to achieve the legendary Phoenix Form, but the process was perilous and uncertain.

However, his research with Gandalf on the magical properties of Thunderbirds had reached a frustrating impasse. Now, with Felix Felicis complete, Sylas saw an opportunity to advance both goals.

He decided to take a measured risk.

He would drink Felix Felicis not for personal gain, but to help design the Thunderbird's magic circulation system, a grand magical reconstruction that could reshape the limits of transformation.

If luck truly guided him, perhaps they could succeed at last.

Gandalf had remained in Rivendell since the engagement, and when Sylas visited to deliver the potions, the wizard immediately agreed to assist. Arwen, concerned but curious, joined them as well.

The three of them gathered atop the vast Mallorn at Weathertop, where the air hummed with power.

Gandalf stroked his beard, looking over the runic circles carved into the wooden floor. "Sylas, what exactly are you planning to do?"

Sylas held up the flask of golden potion, his expression solemn. "This time, I intend to take Felix Felicis and, guided by luck, complete the Thunderbird's magical transformation. But time is limited, and we cannot risk testing on lesser subjects. The procedure will be performed directly on Thorondor. We must aim for success on the first attempt."

He paused, glancing toward the giant Eagle perched nearby, its golden eyes steady and fearless.

"Of course," Sylas continued, "the danger is immense. If Felix Felicis cannot guide us true, the result could be catastrophic. At best, loss of control or sanity. At worst, an explosion that could kill us all."

Turning toward Thorondor, Sylas placed a hand over his heart and asked quietly, "Thorondor, are you certain you wish to take this risk?"

Thorondor lowered his head and fixed Sylas with a steady, unwavering gaze. It was a silent nod filled with determination.

Having received his answer, Sylas did not try to dissuade him further. If Thorondor wished to become stronger, he would respect that wish. He only prayed in silence that Felix Felicis would truly bless them with the luck needed for a safe transformation.

He uncorked the small crystal bottle. The golden potion shimmered like molten sunlight. Pouring out two spoonfuls, he raised it to his lips and drank.

The warmth spread instantly. A soft radiance filled his vision, and a powerful confidence rose within him, washing away hesitation and doubt. Everything seemed connected, clear, within reach.

Gandalf and Arwen watched intently.

"How do you feel?" Gandalf asked.

Sylas smiled broadly. "I feel… great." His eyes gleamed with surety. "Let's begin."

He drew his wand and aimed it at Thorondor. The tip glowed with rippling blue light as he began to cast the advanced Transfiguration spell.

At once, the enormous eagle stirred. The great creature's wings, once spanning nearly fifty meters, began to shrink, feathers shivering as the air crackled with energy. The wings folded inward until they spanned only ten meters, and beneath them grew a second, smaller pair. His tail feathers elongated, splitting into two magnificent plumes that shimmered like phoenix fire.

Thorondor's massive form shifted, but his essence remained. His body still carried the majesty of an eagle, yet his appearance now echoed the mythical Thunderbird.

So far, the transformation was purely external. Inside, he remained unchanged.

But what Sylas intended next was far more dangerous.

The magical energy needed to alter a being of Thorondor's size was immense. Yet Sylas's power, bolstered by his Obscurial core and months of refined magical growth, was more than enough. And with Gandalf, wielder of the Ring of Fire, standing by his side, he feared no exhaustion.

The external shape was only the beginning. Sylas's true challenge lay in reconstructing the magical circulation system, the inner flow of life and power that governed all magical creatures.

He began to channel raw energy into Thorondor, weaving new lines of magic over the old ones.

The eagle trembled violently. Sparks flared across his feathers as his muscles seized under the strain, but he never resisted. He endured in silence, trusting Sylas completely.

Bit by bit, Sylas overlaid the Thunderbird's prototype circuit, the design he and Gandalf had created months ago, onto Thorondor's original system. The air shimmered around them as runes blazed across the platform.

When the final connection locked into place, a surge of energy burst through the air. Lightning crackled along Thorondor's feathers, tracing silver veins of power from beak to tail.

He spread his wings and cried out, releasing a shock of electricity that arced toward the sky.

The transformation was irreversible. Even the strongest counter-Transfiguration spell could no longer return him to his original form.

This, Sylas realized, was their greatest success yet, an evolved form far beyond the earlier experiments.

He and Gandalf had once managed to transform an Acromantula into a weak Thunderbird capable of producing minor static discharges. But Thorondor's raw magical power made him a far greater vessel. The electricity he generated was several times stronger, enough to scorch the air and leave burn marks on the platform.

And yet, it was still not enough.

A true Thunderbird was a being of legend, able to summon storms, command lightning, and call down rain that could blanket entire cities. Compared to that, their creation was only a shadow.

In past experiments, they had hit a dead end. Without records, references, or surviving Thunderbirds to study, they could only speculate.

But now, under the influence of Felix Felicis, something changed within Sylas. His vision sharpened. The patterns of magic that had once seemed incomprehensible now appeared obvious, flawed, almost clumsy.

He saw exactly where the currents were wrong. He knew instinctively how to reroute them.

Guided by a sudden, inexplicable intuition, Sylas began refining the intricate network of magical circuits within Thorondor once more.

He made small adjustments at first, subtle changes to the pattern of energy flow. The moment his wand traced a new arc of magic, a surge of light erupted from Thorondor's feathers. The electricity flared, doubling in brightness, crackling through the air like living thunder.

Sylas's eyes lit up.

"It works!" he breathed.

Encouraged, he continued to modify the remaining pathways, his movements quick and sure, each change guided by instinct as much as intellect.

The inner workings of a magical creature were as delicate and complex as a living meridian map. With every adjustment, the web of magic inside Thorondor grew more refined, smoother, and more complete.

At times, Sylas succeeded purely by luck, shifting a single line of power in just the right way. Each improvement made the eagle's body hum more evenly with energy.

But progress was not always smooth. When he reached the core node of the circulation system, the heart of Thorondor's magic, Sylas altered one delicate channel, and chaos erupted.

The eagle screamed. Lightning exploded from his wings, and violent energy surged through the air. The runic circle beneath them flickered as the magical flow turned unstable.

"Hold on!" Sylas shouted, panic flashing through him. He poured all his strength into suppressing the riot of energy, forcing the currents back under control.

For a terrible moment, he thought he would fail. But then, guided by what felt like pure chance, his hand moved on its own, tracing a new route for the magic flow, a perfect line that stabilized everything.

The chaotic energy settled instantly.

Thorondor's massive body trembled, then released a deep, resonant cry.

The light radiating from him grew brighter, steady and pure.

Time passed quickly. Sylas could feel the influence of Felix Felicis fading. His confidence and insight were still there, but the golden clarity of luck was slipping away. He reached for the potion bottle, preparing to take another sip.

Before he could, Gandalf stepped forward. The old wizard smiled knowingly, uncorking the bottle Sylas had given him earlier.

"This potion truly is extraordinary," he said, taking half the dose. The golden liquid shimmered down his throat. "I feel as though fortune itself has chosen to walk beside me."

A faint golden sheen flickered in Gandalf's eyes. Without hesitation, he raised his staff, channeling his magic into the spellwork.

What followed was nothing short of miraculous.

Under Gandalf's guidance, every mistake Sylas had overlooked became obvious. Each flawed connection in the circuit glowed faintly, and Gandalf adjusted them with elegant precision. His wisdom, amplified by the potion, became almost divine.

He and Sylas worked in perfect synchrony. Where Sylas wove raw magical structure, Gandalf refined it, shaping each node until the entire network pulsed with stable, rhythmic energy.

Even after Sylas's own potion wore off, Gandalf's insight carried them forward. Lightning danced around them like living threads of gold.

At one moment of sudden inspiration, Gandalf lifted his staff toward the sky. He murmured a series of ancient runes, and a bolt of lightning descended, fusing directly into Thorondor's heart.

A thunderous crack echoed through the valley.

Gandalf's lightning-summoning magic merged seamlessly with Sylas's design. Thorondor's new circulation system shone from within, glowing like molten gold through his feathers.

Then, with a final surge of light, the network sealed itself. The flow of magic inside Thorondor stabilized completely.

It was done.

A perfect Thunderbird was born.