Greyback's roar sent an ominous echo rippling through the Forbidden Forest.
Three werewolves, driven forward by his command, burst out from between the trees and lunged once more toward Snape. Among them, the traitor called Viktor ran in front, his yellow fangs gleaming coldly.
"Down!" Hagrid's voice bellowed from behind Snape.
He dropped at once. The giant crossbow hummed with a violent tremor, and a thick oak bolt whistled over Snape's head, burying itself deep into Viktor's abdomen.
Viktor let out a choking whimper, trying to dodge aside, but the spell Greyback aimed at him kept him frozen in place.
"Good shot, Hagrid!" Snape shouted, rolling sharply to one side to dodge Greyback's second flash of green light. In moments like this, standing still and foolishly spinning in hopes of Disapparating away was the least intelligent option.
The Killing Curse struck a nearby beech tree, the trunk exploding instantly into a shower of splinters.
"Run, little rat!" Greyback cackled, his laughter shrill and savage. "The more you run, the sweeter you'll taste later. Let me see how fast a Hogwarts student can scurry!"
Then, a black shadow sprang up from the pile of leaves, Nagini's fangs sank precisely into the leg of the nearest werewolf.
Amid the creature's scream, Snape seized the chance, flicking out three Killing Curses in rapid succession, each jet of green light cutting a deadly line through the dark.
Two fell instantly, but the third, Viktor, managed a sliding crouch that barely saved him from death.
"A snake?" Greyback barked in surprise, raising his wand. "Avada-"
Nagini slithered swiftly across the damp earth, coiling around his arm before he could finish.
"Off!" Greyback roared, shaking his arm violently. Nagini was flung against a tree, letting out a pained hiss.
The disruption made Greyback's curse go wide; he snarled and turned his wand on Nagini again.
Snape's heart clenched. His wand flashed as he hissed, "Sectumsempra!"
An invisible blade slashed across Greyback's chest. The werewolf screamed, but to Snape's alarm, the wound closed almost immediately, sealing through brute regenerative force.
"You're a Hogwarts student, aren't you?" Greyback growled, panting, "Why not join us? The Dark Lord can give you everything, power, position, knowledge, "
Snape's eyes narrowed, the tip of his wand burning bright green. He didn't need anything from Tom. Why would any sane man serve as Tom's hound?
Greyback darted aside with unnatural speed, barking mockingly. "Look at you, so fluent with Unforgivable Curses. Does Dumbledore know what his little student is capable of?"
Snape ignored him, calculating where Greyback would move next and firing relentlessly.
Then, a faint pop split the air. Dobby had returned, bringing with him Albus Dumbledore and the werewolf girl, Lyka Lupa.
The green flashes illuminated Dumbledore's face. Surprise flickered behind the half-moon spectacles, followed by something more complex.
"Professor!" Snape called out.
Greyback ducked behind a tree, his expression shifting when he saw who had arrived. He turned and bolted into the shadows. Viktor, realizing the fight was lost, tried to flee after him.
"Ava, " Snape began to cast, but instantly stopped himself. With Dumbledore here, he adjusted the incantation: "Wingardium Leviosa, drop!"
Viktor's body lifted weightlessly, then slammed down hard, carving a crater in the mud.
There was a faint crack as Greyback disappeared into the dark.
Snape exhaled deeply. He glanced toward Nagini, she was crawling weakly toward him, injured.
He crouched down, letting her slither back onto his arm, checking her carefully.
"That snake..." Hagrid noticed her, his brow furrowing in confusion.
"She's my friend," Snape replied quickly, stroking her head as he whispered a healing charm.
Nagini hissed softly, comforted, and slipped back inside his robe.
"Professor, you finally made it!" Snape greeted Dumbledore eagerly, as if the man who had just been flinging Killing Curses around wasn't him at all. "We almost didn't make it."
As he spoke, he casually flicked a Sectumsempra at the unconscious Viktor, but Dumbledore blocked it with a single wave.
A rope shot from the tip of Dumbledore's wand, binding Viktor tightly.
"If I hadn't come," Dumbledore said, his gaze heavy on Snape, "I fear you'd be the only one left standing."
"How could that be?" Snape gestured at Viktor. "He's still breathing, isn't he? I only used a Levitation Charm, "
"We have to go to the camp!" Lyka interrupted, her voice trembling with urgency. "My packmates are still there!" Her amber eyes burned with fear.
"Professor, let me go too," Snape said, turning to Dumbledore. He had never been to the werewolves' encampment deep in the forest and couldn't reach it alone.
"Hagrid, Dobby, secure the area." Dumbledore nodded once, then extended his arms. "Hold on."
Snape and Lyka each grabbed one of his hands.
A suffocating pressure closed around them, and then they appeared in a hidden clearing deep in the forest.
What greeted them was devastation.
The werewolf encampment, once a cluster of tattered tents and crude wooden huts, was now reduced to ruin.
Tents lay in shreds; the ground was soaked in blood and claw-marked from violent struggle. Several campfires still smoldered, curling up faint wisps of smoke.
Bodies lay everywhere in twisted shapes. The air stank of blood and wild animal musk.
Lyka let out a sound between a wail and a howl, staggering forward to kneel beside the nearest corpse. It was an elderly male werewolf, his chest torn open, eyes still frozen in terror.
"Uncle Norton..." she whispered, her trembling fingers brushing his pale face.
"No... no..." She crawled to another body, a young female werewolf, her golden hair matted dark with blood. "Mara..."
Snape scanned the area calmly. He counted at least seven dead, and several others breathing faintly, each one wounded.
He approached an older male werewolf whose abdomen had been ripped apart.
"Don't move," Snape ordered curtly, drawing his wand to begin healing.
"I'm so sorry, child," Dumbledore murmured, laying a gentle hand on Lyka's shoulder. "No one should have to endure such loss."
"Why did they do this?" Lyka cried, raising her tear-streaked face, eyes blazing with hatred. "We only wanted to live quietly! We never hurt anyone!"
"Mara's dead, Norton's dead, Karl's dead..." Her voice cracked; her fists clenched so hard that her nails dug into her palms.
"What good is crying?" Snape said without looking up, continuing his spellwork. "If you have time to weep, use it to kill more of them."
"What else can I do?" Lyka screamed hoarsely, turning on him. "We don't even have wands! When we transform, we can't control ourselves! How can we even avenge them..." Her voice trailed off.
"Violence only breeds more violence," Dumbledore sighed. "Revenge will not mend what's been broken. You still have the living to care for."
Snape snorted but said nothing. He finished tending to the last wounded werewolf and stood, brushing the dirt from his robes.
The night's events stirred an old memory, Albania, that hag who had used werewolves as experimental subjects. From her, he'd taken a roll of yellowed parchment and a necklace strung with a blood-red canine fang.
Snape pulled both from his pocket.
The moment he did, Dumbledore's eyes flicked to them. "Severus, what is that? I can sense dark magic upon it."
"I know," Snape said steadily. "I got these in the Albanian woods from an old witch. She used them to control werewolves. I saw her force one to transform outside the full moon."
He briefly recounted the encounter.
"She also used some kind of song to control them," Snape lifted the parchment slightly, "but it's not recorded here. What is written down is how to induce transformation outside the full moon."
"And," Snape added after a pause, "Professor, you've seen the Daily Prophet mention the Wolfsbane Potion, it lets a werewolf retain sanity during transformation. Perhaps we could improve on it."
"You mean..." Lyka's eyes lit up. She nearly lunged toward him. "If that's true... control during transformation... remaining conscious..."
"Patience," Snape stepped back slightly, giving her a measured look. "In theory, yes. It could let you fight back. But it's incomplete, more tests would be needed, which means more werewolf volunteers."
"Severus, this is not acceptable," Dumbledore said sharply. "These survivors have suffered enough. They need healing and protection, not more experiments."
"I'll do it!" Lyka blurted, desperate. "Please, give us the parchment."
"Professor," Snape said calmly, glancing at Dumbledore, "it seems Lyka has made her choice. Even if I don't give it now, she'll seek me out later."
Dumbledore removed his glasses, rubbing the bridge of his nose wearily.
"But I can't just hand this over," Snape continued, turning to Lyka. "It's too dangerous. If the Dark Lord got it, he could build an army of werewolves."
"As long as I can avenge them, I'll do anything!" Lyka said.
"If you'll do anything," Snape replied, "then I'll need you to make an Unbreakable Vow. If Professor Dumbledore agrees, he can serve as witness."
"Professor, please," Lyka pleaded, tears spilling down again. She pointed to Mara's body, choking on her words. "She... she used to be a healer at St. Mungo's. A patient bit her on purpose, she became a werewolf. Before coming here, she used to lock herself in her cellar every full moon, terrified of hurting anyone. Greyback killed her anyway... I have no other choice..."
Dumbledore's gaze swept the camp, the dead, Lyka, Snape, and the parchment.
He was silent for a long time. So long that Snape thought he might refuse.
Finally, Dumbledore nodded heavily. "If this is what you both choose... though I cannot condone it, I will bear witness."
Lyka exhaled shakily in relief, then stepped forward, meeting Snape's eyes. "If I can avenge them, I'll take any oath."
Snape extended his hand. She grasped it tightly. Her palm trembled, but her grip was firm.
Dumbledore drew his wand and placed its tip against their joined hands.
Snape spoke first.
"Lyka Lupa, upon receiving the parchment and necklace concerning werewolf transformation, do you swear to keep all related knowledge secret, holding it solely within your possession?"
"I do." Lyka's answer was firm.
A thin, dazzling flame shot from the wand, a strand of molten light wrapping their clasped hands.
"Do you swear never to stand in opposition to Severus Snape, that is, myself, nor take arms against me?"
Dumbledore's wand trembled. Lyka looked at him, then nodded.
"I do," she said.
A second flame twined around the first, forming a glowing, red chain.
Dumbledore's frown deepened, but he didn't withdraw his wand.
"And lastly," Snape said quietly, his black eyes locked on her amber ones, choosing his words with precision, "so long as I act without deliberate malice toward you, do you swear to do your utmost to heed my commands and carry out the tasks I assign you?"
Her hand trembled within his, but she didn't pull away.
Dumbledore watched them intently, especially Snape, his wand hovering over their hands as if questioning whether this ritual should continue.
"I do," Lyka said finally, drawing a deep breath.
Their faces glowed red under the light of the third flame. It burst from the wand and wove together with the other two, coiling tightly around their clasped hands like a burning serpent.
The light slowly faded as the vow was sealed.