"Hogwarts Sign-in System: Dol Guldur detected. Do you wish to sign in?"
Before Sauron even appeared, the Sign-in System reacted first.
"Sign in!" Luke silently chanted.
"Sign-in successful. Congratulations on obtaining 'Advanced Dark Arts Revealed'!"
Looking at the Dark Arts book that appeared before him, Luke's mind was shaken.
He hadn't expected to get this item from a sign-in this time.
Although it wasn't the time to read, Luke still couldn't help but secretly flip through the contents of the book, dedicating a portion of his mind to it.
"Imperio, Crucio, Avada Kedavra, Fiendfyre Curse—and Horcrux creation!"
The more Luke read, the more his mind was shaken.
The rewards from this sign-in were too great! It almost covered the most powerful Dark Arts in the magic world.
If he could fully master these Dark Arts, his strength would undoubtedly undergo earth-shattering changes.
However, the most pressing matter was still the Avada Kedavra.
As one of the three Unforgivable Curses, Avada Kedavra causes instant death upon impact, and no magic can block it, making it the most dangerous and lethal Dark Arts in the magic world.
But it was also the easiest Dark Arts to learn.
It didn't require complex casting conditions; only the most extreme and intense emotions were needed. By channeling magic with malice and murderous intent, one could successfully cast Avada Kedavra.
The power of Avada Kedavra depended on the caster's malice and magic.
However, before Luke had more time to read, a terrifying dark power surged from all directions, like towering waves threatening to crush them.
Gandalf swiftly used his staff to erect a massive Holy Light barrier, protecting everyone.
Looking at the fluctuating Holy Light barrier, it seemed like a bubble in a raging sea, constantly on the verge of being breached.
"Gandalf, I'll help you!"
Radagast, for the first time, displayed the power of a Brown Wizard. His staff released another Holy Light barrier, reinforcing Gandalf's barrier and making it even sturdier.
Glorfindel radiated immense power and dazzling Holy Light, tearing a huge rift in the darkness, allowing a ray of sunlight to pour down from the dim sky, illuminating everyone and stopping the invasion of darkness.
Meanwhile, Elrond chanted ancient and mysterious Elvish, controlling the element of wind to form a hurricane that continuously swept through the entire Castle cave, determined to ferret out the hidden enemy within.
"He's hiding there!" Elrond's sharp gaze instantly fell on the highest, ruined tower.
The hurricane also swiftly rushed towards that tower.
"Confringo!" Luke cast the spell towards the tower without hesitation.
With a huge explosion, the tower was destroyed in the hurricane and explosion.
As the rubble fell, the enemy hidden within was exposed.
A massive red flame erupted from it, emitting a scorching and evil aura, coalescing into an impossibly huge fiery vertical eye.
"You cannot defeat me. Darkness rises again. Your faint light is isolated in the darkness, so small."
A voice filled with evil, temptation, and corruption echoed in everyone's ears.
The nine Nazgûl, whom they had previously dealt with, were resurrected from that fiery giant eye, surrounding the group from all directions.
Within the giant vertical eye was a dark void, and a very tall figure emerged from it, releasing a powerful and terrifying dark power, which crashed like an overwhelming tide against the Holy Light barrier sustained by Gandalf and Radagast.
The Holy Light barrier was on the verge of collapse.
The sky, moreover, plunged into complete darkness, as if all light had been swallowed.
Luke felt a terrifying sense of suffocating pressure, and it seemed as if countless evil voices were tempting him, attempting to corrupt his mind.
He quickly summoned his Patronus to his side, and only under the Patronus's power did he get a chance to breathe, like someone who had been suffocating for a long time finally emerging from water and gasping for air.
At the same time, he felt a warm energy from his chest pocket.
Luke's eyes lit up, and he quickly pulled a handkerchief from his pocket. Opening it, he saw five strands of golden hair emitting a silver glow.
It was the hair Galadriel had given him earlier.
He wove two strands of golden hair into a bracelet with his wand and then put it on his right hand.
Galadriel's hair contained the radiance of the Two Trees, instantly blocking the dark power's erosion of his mind, making him no longer affected. Luke watched as Gandalf, Radagast, Elrond, and Glorfindel successfully joined forces to resist Sauron's attack, and he breathed a sigh of relief.
It was fortunate that he had invited Elrond, Glorfindel, and Radagast, these three powerful helpers.
Otherwise, with just Gandalf and himself, they would probably have walked straight into a tiger's den.
"The age of Elves is over, the age of Orcs has arrived. You are fading, and I shall be the victor!"
The fiery giant eye erupted with even hotter flames, and from within the dark void of the vertical pupil, the tall figure stepped out.
Evil aura and terrifying dark power swirled around his body. He was clad in dark, grotesque armor, his figure tall and indistinct, shrouded in black mist and flames.
Seeing Sauron appear in his true form, everyone was greatly shocked and disbelieving.
Radagast exclaimed in horror, "He has a physical form! Has he truly been resurrected?"
"How is this possible? Unless he has regained the one ring, he cannot have a physical form." Elrond was also unwilling to believe it. Gandalf shook his head with a solemn expression: "Relax, Radagast, he is not truly resurrected with a physical form yet, otherwise we would have already fallen."
"Thráin II, the last owner of the seven Dwarf rings decades ago, was attacked and captured by Orcs and imprisoned in Dol Guldur. I think it was then that he obtained the seven Dwarf rings and gained a portion of his power through them."
Sauron's appearance greatly startled everyone, and the power he displayed also made them uneasy.
As Sauron approached through the air, that powerful dark force compelled the Holy Light barrier to shrink more and more.
With a powerful strike from Sauron, the Holy Light barrier was shattered, and Gandalf and Radagast were exhausted, unable to fight further.
"Sauron, servant of Morgoth, your opponent is I!"
Glorfindel unleashed a holy and powerful force, standing on equal footing with Sauron's dark power.
As the reborn Lord of the Golden Flower, he possessed pure magic comparable to a Maia, making him one of the strongest Elves in Middle-earth.
Now, facing the returned Sauron, he still did not fall behind.
"Glorfindel, the reborn Elf, I wonder if you will have a chance to be reborn again if I kill you this time?" Sauron's mocking voice echoed around, carrying a terrifying power.
With that, an even more terrifying power struck Glorfindel, forcing him back a few steps, and the light on his body dimmed somewhat.
Meanwhile, Elrond was entangled and besieged by the nine Nazgûl, unable to provide support for a moment.