The descent into the bowels of the Black Lighthouse felt like walking backward through time. The spiral staircase was hewn from the living rock of the island, slick with centuries of sea spray and silent magic. With every step downward, the air grew colder, heavier, charged with a hum that Lucien felt vibrating in the marrow of his bones.
They emerged into a vast, circular chamber that occupied the base of the structure. It was a cavernous space, illuminated not by windows, but by a central, suspended brazier burning with a pale, smokeless violet fire. The walls were lined with shelves carved directly into the stone, filled with books bound in dragon-hide, jars of suspended liquids, and artifacts that seemed to absorb the light rather than reflect it.
It was a library of the forbidden. A sanctuary for the things the Ministry burned.
Lysander Grindelwald moved to the center of the room, his robes whispering against the stone floor. He turned to face them, his expression shifting from that of a savior to that of a harsh, exacting master.
"The world outside believes magic is a gift," Lysander began, his voice echoing in the chamber. "A whimsical tool for cleaning dishes or stunning rivals. But you, Lucien, know the truth now. Magic is a current. It is pressure. And right now, you are a vessel with cracks in the hull."
Lucien leaned against a heavy wooden table, his legs trembling. The exhaustion was still there, but the fear was sharper. "You saw what happened in the woods," he said, looking at his hands. "I nearly brought the whole forest down. I don't know how to stop it."
"Because you were trying to suppress it," Lysander countered sharply. "Your mother's potion forced the water back into the dam. Now the dam is gone. You cannot stop the river, Lucien. You must dig a channel."
He waved a hand, and the violet fire in the brazier roared, leaping unnaturally high, twisting into the shape of a snarling dragon, then a phoenix, then a simple, perfect sphere.
"Your father, Harry Potter, was a master of defensive magic," Lysander said, pacing slowly. "He fought to protect the world as it was. His magic was reactive. A shield. A Patronus. Noble, yes. But limited."
Lysander stopped directly in front of Lucien, his blue eyes piercing. "We are not trying to preserve the world, Lucien. We are trying to survive it. And to survive what is coming—Hermione Granger, the Ministry, the old prejudices—you need magic that is proactive. You need the magic of intent. The magic your father feared."
"Dark Arts," Ira said from the shadows of the room. She was running her hand along the spine of an ancient tome, her face unreadable. "You want to teach him to hurt people."
"I want to teach him to end threats," Lysander corrected smoothly. "There is no light or dark, Ira. There is only power, and the intent behind it. A Stunning Spell can leave a man to freeze to death. A Killing Curse is instantaneous mercy. The morality is in the wizard, not the wand."
He turned back to Lucien. "Lesson one. Domination of the Elements."
Lysander pointed to a heavy, iron cauldron sitting in the corner. "Move it. No wand. No words."
Lucien blinked. "I... I've never cast a spell without a..." He stopped. He realized he had. In the woods. The branches. The ward.
"Don't ask it to move," Lysander instructed, his voice dropping to a whisper. "Don't wish for it. Will it. Your magic is currently a scream. Make it a command. Visualize the space the iron occupies, and simply... decide it is elsewhere."
Lucien focused on the cauldron. He felt the reservoir of power inside him—the terrifying, churning ocean that the locket had hidden. He tried to push it toward the iron.
Move.
Nothing happened.
Move!
He gritted his teeth, the sweat breaking out on his forehead. He shoved the energy outward with a grunt of frustration.
BOOM.
The cauldron didn't move. Instead, it crumpled inward as if crushed by a giant, invisible fist. The metal screeched and tore. At the same time, a shockwave blasted outward, knocking a row of books off the shelves and sending Ira stumbling back against the wall.
Lucien gasped, recoiling, pulling his hands back as if burned. "I didn't... I didn't mean to..."
"Raw force," Lysander observed, unperturbed, though he had cast a silent Shield Charm around himself. "Crude. Violent. Typical of the Potter line when emotional. You treat magic like a bludgeon."
"I can't control it!" Lucien shouted, his voice cracking. "It's too much!"
"It is exactly enough," Lysander snapped. "But you are afraid of it. You are afraid of yourself."
He looked at Ira. "Step forward, Miss Riddle."
Ira hesitated, then moved into the light of the violet fire. She looked from the crushed cauldron to Lucien's terrified face.
"Lucien is afraid he will hurt you," Lysander stated calmly. "That fear is the shackle. It makes his magic erratic." He looked at Lucien. "If you do not learn to channel this cleanly, you will hurt her. The Ministry will not crush her; you will, by accident."
The words hit Lucien harder than any spell. He looked at Ira—the girl he had saved, the girl who looked at him with that guarded trust.
"Focus on her," Lysander commanded. "Not on the iron. Focus on Ira. She is the anchor. The reason. Don't move the object because you are told to. Move it because it is in her way."
Lysander flicked his hand, and the crumpled remains of the heavy cauldron levitated, hovering precariously directly above Ira's head.
"No!" Lucien lunged forward.
"Don't run," Lysander barked. "Cast. Move it aside. Gently. Or it falls."
The cauldron wobbled. Gravity began to take hold.
Lucien froze. He looked at Ira. She didn't flinch. She didn't look at the heavy iron threatening to crush her skull. She looked straight at him, her dark eyes locking onto his green ones. She trusted him.
The light in the shadow.
Lucien didn't think about the magic. He didn't think about the locket or the lies. He just thought about her. He thought about the space above her head being empty. He visualized the safety of the air around her.
He didn't shove the power this time. He guided it. He reached out with his mind, wrapping the chaotic green energy around the iron, feeling its weight, its texture.
Aside.
He swept his hand to the left.
There was no explosion. No shockwave. The crushed cauldron moved swiftly, silently, and smoothly through the air, setting down on the stone floor three feet away with a barely audible clink.
Silence filled the room.
Lucien stared at his hand, breathing heavily. The magic felt... different. Not like an explosion, but like a muscle flexing. It felt intoxicating.
"Better," Lysander said quietly. "That was not the magic of a shield, Lucien. That was the magic of control. You imposed your will upon reality to alter the outcome."
He walked over, placing a hand on Lucien's shoulder. "That is the first step of the Dark Arts. The refusal to accept the world as it is presented to you."
Lysander looked at the two of them—the exhausted boy vibrating with power, and the non-magical girl who had been the catalyst.
"Rest now," he ordered. "Tomorrow, we begin the theory. Because soon, Hermione Granger will stop looking for a boy running away, and start looking for a boy preparing for war."
Lucien looked at Ira, and in the violet light, he saw a faint, terrified smile touch her lips. He had controlled it. For her. And for the first time, the "Dark Arts" didn't feel dark at all. They felt like salvation.